University of Groningen Gold(I) Catalysis Taschinski, Svenja

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Gold(I) Catalysis

Taschinski, Svenja

DOI:

10.33612/diss.126022756

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Publication date:

2020

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Taschinski, S. (2020). Gold(I) Catalysis: Mechanistic Insights, Reactivity of Intermediates and its

Applications. University of Groningen. https://doi.org/10.33612/diss.126022756

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Chapter 6 Experimental Sections and

Appendices

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98

6.1)

Experimental Sections, General Procedures

6.1.1) GP A: Sonogashira Coupling of Alkynes

Sonogashira coupling products were synthesized according to a modified procedure previously reported by Wegner and co-workers.[1]

2-Iodophenol 43 (1.00 eq), copper(I) iodide (5.00 mol-%) and Pd(PPh3)2Cl2 (2.50 mol-%)

were dissolved in freshly degassed solvent in a heat-gun dried Schlenk tube under an atmosphere of nitrogen. A small excess (1.20 eq) of alkyne 68 was added and the resulting mixture was stirred at room temperature until complete conversion was determined by TLC. The mixture was diluted with water and the phases were separated. The aqueous layer was extracted three times with ethyl acetate, the combined organic layers were separated, dried over sodium sulfate and evaporated onto Celite®_{. The crude products 25 were purified by flash}

column chromatography.

6.1.2) GP B: Synthesis of Diazonium Salts

Diazonium salts were synthesized according to a modified procedure previously reported by Tóth and co-workers.[2]

Tetrafluoroboronic acid (48% in water, 2.60 eq) was dissolved in 4.00 mL water, aniline 69 (1.00 eq) was added at 0 °C and the mixture was stirred for 30 minutes. A solution of sodium nitrite (1.00 eq) in 1.50 mL water was added dropwise and the resulting mixture was stirred for 30 minutes. The mixture was filtered and the residue was dissolved in a minimum amount of acetone and precipitated with diethyl ether. The products 34 were collected by filtration and washed with diethyl ether.

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6.1.3) GP C: Synthesis of Azobenzofurans

IMesAuNTf2 (5.00 mol-%) and 2,6-ditertbutylpyridine (1.20 eq) were dissolved in

dichloromethane and stirred for ten minutes. Aryldiazonium tetrafluoroborate 34 (3.00 eq), molecular sieves (3 Å) and o-alkynylphenol 25 (1.00 eq) were added and the mixture was stirred for the mentioned time at room temperature. The mixture was evaporated onto Celite®

and purified by flash column chromatography.

6.1.4) GP D: Synthesis of Gold(I) Complexes

Gold(I) complexes were synthesized according to a modified procedure previously reported by Hashmi and co-workers.[3]

In a heat-gun dried Schlenk tube, LAuCl 38 (1.00 eq) and AgOTs (1.00 eq) were dissolved in 50.0 mL THF and stirred for one hour at room temperature under exclusion of light. Triethylamine (7.00 eq) and substituted p-(phenylethynyl)phenol 25 (1.02/1.05 eq) were added and the mixture was stirred for the mentioned time at room temperature. The mixture was filtered through a pad of neutral Al2O3 and evaporated at room temperature. The crude

solids were recrystallized from dichloromethane/pentane, filtered and washed with pentane to give the products 46.

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100

6.1.5) GP E: Kinetic Experiments using Vinyl Gold(I) Complexes

400 µL of a stock solution of gold(I) complex 46 in CDCl3 (Stock solution: 6.25 mM including

10 µL tetrachloroethane in 3 mL CDCl3 as internal standard, CDCl3 freshly filtered over

K2CO3) and 100 µL of a stock solution of 4-bromophenol 70Br in CDCl3 (Stock solution in

CDCl3 freshly filtered over K2CO3) were added to a NMR tube and the mixture was shaken

vigorously. The reaction was monitored with 1_{H NMR spectroscopy (500 MHz) until complete}

conversion was reached.

6.1.6) GP F: Synthesis of Diynes via Sonogashira Coupling

Sonogashira coupling products were synthesized according to a modified procedure previously reported by Tsuji and co-workers.[4]

2-(2,5-Halogen-4-(cyclohexyloxy)phenoxy)tetrahydro-2H-pyran 58 (1.00 eq), copper(I) iodide (10.0 mol-%) and Pd(PPh3)2Cl2 (5.00 mol-%) were dissolved in freshly degassed solvent in a

heat-gun dried Schlenk tube under an atmosphere of nitrogen. A small excess (2.40 eq) of alkyne 68 was added and the resulting mixture was stirred at 60 °C until complete conversion was detected by TLC. The mixture was diluted with water and the phases were separated. The aqueous layer was extracted three times with ethyl acetate, the combined organic layers were separated, dried over sodium sulfate and evaporated onto Celite®_{. The crude}

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101

6.1.7) GP G: Deprotection of Diynes

Deprotected Diols were synthesized according to a modified procedure previously reported by Tsuji and co-workers.[4]

THP-protected alkynediol 59 (1.00 eq) was dissolved in a mixture of CH2Cl2 / MeOH (v/v, 1:1)

and p-toluenesulfonic acid monohydrate 71 (10.0 mol-%) was added at room temperature. The mixture was stirred until complete conversion was detected by TLC. Water was added and the aqueous layer was extracted three times with ethyl acetate. The organic layer was dried over sodium sulfate and evaporated onto Celite®_{. Purification by flash column}

chromatography yielded the products 55.

6.1.8) GP H: Gold-Catalyzed Reactions of Diynes

Gold-catalyzed reactions were performed according to a modified procedure previously published by Klein and co-workers.[5]

Substituted alkynediol 55 (1.00 eq), Ph3PAuCl (20.0 mol-%), NaHCO3 (4.00 eq) and

p-benzenediazonium tetrafluoroborate 34 (6.00 eq) were dissolved in 2.00 mL acetonitrile and the mixture was stirred for the mentioned time under blue LED irradiation (450 nm) at room temperature. The mixture was evaporated onto Celite®_{. Purification by flash column}

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6.2)

Experimental Section, Chapter 2

6.2.1) Synthesis of Substrates

6.2.1.1) 2-(2-Iodophenoxy)tetrahydro-2H-pyran

In a heat-gun dried Schlenk tube, 2-iodophenol 43 (3.28 g, 14.9 mmol, 1.00 eq) was dissolved in 3,4-dihydro-2H-pyran (12.6 mL, 12.5 g, 149 mmol, 10.0 eq) and stirred for ten minutes at room temperature. PPTS (74.9 mg, 298 µmol, 2.00 mol-%) was added and the solution was stirred for 16 hours at room temperature. Saturated sodium hydrogencarbonate solution was added and the aqueous layer was extracted three times with ethyl acetate, dried over MgSO4

and evaporated onto Celite®_{. Purification by flash column chromatography (SiO}

2, PE/EA,

20:1) yielded the product 44 as a light yellow oil (4.24 g, 13.9 mmol, 93%).

TS-027 Rf (SiO2, PE/EA, 10:1) = 0.54; 1H NMR (300.51 MHz, CDCl3):  = 1.16-2.25 (m, 6 H),

3.57-3.64 (m, 1 H), 3.88 (dt, J = 11.0 Hz, J = 2.84 Hz, 1 H), 5.54 (t, J = 2.84 Hz, 1 H), 6.73 (dt, J = 7.69 Hz, J = 1.36 Hz, 1 H), 7.08 (dd, J = 8.26 Hz, J = 1.36 Hz, 1 H), 7.24-7.30 (m, 1 H), 7.77 (dd, J = 7.69 Hz, J = 1.53 Hz, 1 H) ppm. The spectroscopic data matches previously reported data.[6]

6.2.1.2) 2-(2-(Phenylethynyl)phenoxy)tetrahydro-2H-pyran

According to GP A, 2-(2-iodophenoxy)tetrahydro-2H-pyran 44 (5.00 g, 16.4 mmol, 1.00 eq) was dissolved in 30 mL triethylamine, bis(triphenylphosphine)palladium(II) dichloride (288 mg, 411 µmol, 2.50 mol-%), copper iodide (157 mg, 822 µmol, 5.00 mol-%) and phenylacetylene 68H (2.71 mL, 2.52 g, 24.7 mmol, 1.50 eq) were added

and the mixture was stirred at room temperature for 20 hours. Purification by flash column chromatography (SiO2, PE/EA, 50:1) yielded the product 45 (3.86 g, 13.9 mmol, 84%) as a

brownish oil.

TS-172 Rf (SiO2, PE/EA, 10:1) = 0.54; 1H NMR (300.51 MHz, CDCl3):  = 1.46-1.71 (m, 3 H),

1.75-2.14 (m, 3 H), 3.52 (td, J = 11.0 Hz, J = 2.85 Hz, 1 H), 3.93 (dt, J = 11.0 Hz, J = 2.85 Hz, 1 H), 5.51 (t, J = 2.85 Hz, 1 H), 6.89 (t, J = 7.20 Hz, 1 H), 7.06 (d, J = 8.20 Hz, 1 H), 7.12 (d, J = 8.20 Hz, 1 H), 7.20-7.28 (m, 3 H), 7.39-7.46 (m, 3 H) ppm. The spectroscopic data matches previously reported data.[7]

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6.2.1.3) 2-(4-Tolylethynyl)phenol

According to GP A, 2-iodophenol 43 (2.00 g, 9.09 mmol, 1.00 eq) was dissolved in 50 mL THF, bis(triphenylphosphine)palladium(II) dichloride (160 mg, 227 µmol, 2.50 mol-%), copper iodide (86.6 mg, 455 µmol, 5.00 mol-%), diisopropylamine (1.28 mL, 920 mg, 9.09 mmol, 1.00 eq) and 1-ethynyl-4-methylbenzene 68Me (1.38 mL,

1.27 mg, 10.9 mmol, 1.20 eq) were added and the mixture was stirred at room temperature for 16 hours. Purification by flash column chromatography (SiO2, PE/EA, 100:1) yielded the product 25Me (1.77 g,

8.50 mmol, 93%) as a light brown, crystalline solid.

TS-648 Rf (SiO2, PE/EA, 10:1) = 0.42; 1H NMR (299.95 MHz, CD2Cl2):  = 2.38 (s, 3 H),

5.89 (s, 1 H), 6.88-6.99 (m, 2 H), 7.17-7.27 (m, 3 H), 7.40-7.48 (m, 3 H) ppm. The spectroscopic data matches previously reported data.[8]

6.2.1.4) 2-((4-Methoxyphenyl)ethynyl)phenol

According to GP A, 2-iodophenol 43 (2.27 g, 10.3 mmol, 1.00 eq) was dissolved in 20 mL toluene, bis(triphenylphosphine)palladium(II) dichloride (181 mg, 258 µmol, 2.50 mol-%), copper iodide (98.3 mg, 516 µmol, 5.00 mol-%), diisopropylamine (1.46 mL, 1.04 g, 10.3 mmol, 1.00 eq) and 1-ethynyl-4-methoxybenzene 68OMe

(1.47 mL, 1.50 g, 11.4 mmol, 1.10 eq) were added and the mixture was stirred at room temperature for four hours. Purification by flash column chromatography (SiO2, PE/EA, 50:1) yielded the

product 25OMe (1.67 g, 7.45 mmol, 72%) as a light yellow solid.

TS-229-B Rf (SiO2, PE/EA, 10:1) = 0.26; 1H NMR (300.51 MHz, CD2Cl2):  = 3.83 (s, 3 H),

5.87 (bs, 1 H), 6.88-6.97 (m, 4 H), 7.23-7.29 (m, 1 H), 7.41 (dd, J = 7.68 Hz, J = 1.46 Hz, 1 H), 7.50 (dt, J = 8.93 Hz, J = 2.16 Hz, 2 H) ppm. The spectroscopic data matches previously reported data.[9]

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104

6.2.1.5) 2-(Phenylethynyl)phenol

According to GP A, 2-iodophenol 43 (2.27 g, 10.3 mmol, 1.00 eq) was dissolved in 20 mL toluene, bis(triphenylphosphine)palladium(II) dichloride (181 mg, 258 µmol, 2.50 mol-%), copper iodide (98.3 mg, 516 µmol, 5.00 mol-%), diisopropylamine (1.46 mL, 1.04 mg, 10.3 mmol, 1.00 eq) and phenylacetylene 68H (1.18 mL, 1.16 g,

11.4 mmol, 1.10 eq) were added and the mixture was stirred at room temperature for four hours. Purification by flash column chromatography (SiO2, PE/EA, 100:1 -> 50:1) yielded the product 25H (1.95 g,

10.0 mmol, 97%) as a light yellow solid.

TS-228-A Rf (SiO2, PE/EA, 10:1) = 0.44; 1H NMR (300.51 MHz, CD2Cl2):  = 5.88 (s, 1 H),

6.90-6.99 (m, 2 H), 7.25-7.32 (m, 1 H), 7.36-7.46 (m, 4 H), 7.53-7.60 (m, 2 H) ppm. The spectroscopic data matches previously reported data.[10]

6.2.1.6) 2-((4-Fluorophenyl)ethynyl)phenol

According to GP A, 2-iodophenol 43 (1.20 g, 5.45 mmol, 1.00 eq) was dissolved in 20 mL toluene, bis(triphenylphosphine)palladium(II) dichloride (95.7 mg, 136 µmol, 2.50 mol-%), copper iodide (51.9 mg, 273 µmol, 5.00 mol-%), diisopropylamine (770 µL, 552 mg, 5.45 mmol, 1.00 eq) and 1-ethynyl-4-fluorobenzene 68F (688 µL, 721 mg,

6.00 mmol, 1.10 eq) were added and the mixture was stirred at room temperature for three hours. Purification by flash column chromatography (SiO2, PE/EA, 50:1) yielded the product 25F (902 mg,

4.25 mmol, 78%) as a light brown, crystalline solid.

TS-231 Rf (SiO2, PE/EA, 4:1) = 0.57; 1H NMR (300.51 MHz, CDCl3):  = 5.76 (s, 1 H), 6.91 (dt,

J = 7.62 Hz, J = 1.05 Hz, 1 H), 6.97 (dd, J = 7.62 Hz, J = 0.66 Hz, 1 H), 7.08 (tt, J = 8.71 Hz, J = 2.79 Hz, 2 H), 7.25-7.31 (m, 1 H), 7.41 (dd, J = 7.62 Hz, J = 1.59 Hz, 1 H), 7.50-7.57 (m, 2 H) ppm; 19_{F NMR (282.76 MHz, CDCl}

3):  = -109.89 (s) ppm. The spectroscopic data

matches previously reported data.[1]

6.2.1.7) 2-((4-(Trifluoromethyl)phenyl)ethynyl)phenol

According to GP A, 2-iodophenol 43 (2.00 g, 9.09 mmol, 1.00 eq) was dissolved in THF, bis(triphenylphosphine)palladium(II) dichloride (160 mg, 227 µmol, 2.50 mol-%), copper iodide (86.6 mg, 455 µmol, 5.00 mol-%), diisopropylamine (1.28 mL, 920 mg, 9.09 mmol, 1.00 eq) and 1-ethynyl-4-(trifluoromethyl)benzene 68CF3 (1.63 mL, 1.70 g,

10.0 mmol, 1.10 eq) were added and the mixture was stirred at room temperature for 24 hours, worked up and purified by flash column chromatography. Due to not full conversion of the starting material, the procedure was repeated two times and purification by flash column chromatography (SiO2,

PE/EA, 20:1) yielded the product 25CF3 (120 mg, 459 µmol, 5%) as a light brown, crystalline

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105

TS-626-III Rf (SiO2, PE/EA, 10:1) = 0.50; 1H NMR (399.82 MHz, CDCl3):  = 5.74 (s, 1 H),

6.94 (td, J = 7.53 Hz, J = 1.12 Hz, 1 H), 7.00 (dd, J = 8.27 Hz, J = 1.09 Hz, 1 H), 7.31 (ddd, J = 8.78 Hz, J = 7.30 Hz, J = 1.66 Hz, 1 H), 7.44 (dd, J = 7.70 Hz, J = 1.66 Hz, 1 H), 7.64 (s, 4 H) ppm; 19_{F NMR (376.17 MHz, CDCl}

3):  = -62.90 (s, 3 F) ppm. The spectroscopic data

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6.2.2) Synthesis of Diazonium Salts

6.2.2.1) Benzenediazonium tetrafluoroborate

According to GP B, tetrafluoroboronic acid (48% in water, 5.55 mL, 7.66 g, 41.9 mmol, 2.60 eq) was dissolved in 10.0 mL water, aniline 69H (1.47 mL, 1.50 g,

16.1 mmol, 1.00 eq) was added at 0 °C and stirred for 60 minutes. A solution of sodium nitrite (1.11 g, 16.1 mmol, 1.00 eq) in 2.00 mL water was added dropwise and the resulting mixture was stirred for 60 minutes. The product 34H (2.35 g,

12.3 mmol, 76%) was isolated as a colorless solid.

TS-694 1_{H NMR (299.95 MHz, CD}

3CN):  = 7.90-7.99 (m, 2 H), 8.40 (tt, J = 8.08 Hz,

J = 1.22 Hz, 1 H), 8.44-8.51 (m, 2 H) ppm; 19_{F NMR (282.21 MHz, CD}

3CN):  = -151.73 (s,

4 F) ppm. The spectroscopic data matches previously reported data.[2]

6.2.2.2) 4-Methylbenzenediazonium tetrafluoroborate

According to GP B, tetrafluoroboronic acid (48% in water, 3.45 mL, 4.76 g, 26.0 mmol, 2.60 eq), 4-methylaniline 69Me (1.07 g, 10.0 mmol, 1.00 eq), sodium

nitrite (690 mg, 10.0 mmol, 1.00 eq). The product 34Me (342 mg, 1.66 mmol, 17%)

was isolated as a light purple, crystalline solid.

TS-590 1_{H NMR (399.82 MHz, DMSO-d}

6):  = 2.58 (s, 3 H), 7.80 (d, J = 8.34 Hz,

2 H), 8.55 (d, J = 8.34 Hz, 2 H) ppm; 19_{F NMR (376.17 MHz, DMSO-d}

6):  = -148.32 (s,

4 F) ppm. The spectroscopic data matches previously reported data.[12]

6.2.2.3) 4-Methoxybenzenediazonium tetrafluoroborate

According to GP B, tetrafluoroboronic acid (48% in water, 3.45 mL, 4.76 g, 26.0 mmol, 2.60 eq), 4-methoxyaniline 69OMe (1.23 g, 10.0 mmol, 1.00 eq), sodium

nitrite (690 mg, 10.0 mmol, 1.00 eq). The product 34OMe (745 mg, 3.36 mmol, 34%)

was isolated as a light purple, crystalline solid.

TS-591 1_{H NMR (399.82 MHz, DMSO-d}

6):  = 4.04 (d, J = 1.14 Hz, 3 H), 7.48 (dd,

J = 9.25 Hz, J = 1.21 Hz, 2 H), 8.58-8.64 (m, 2 H) ppm; 19_{F NMR (376.17 MHz, DMSO-d} 6):

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6.2.2.4) 4-Fluorobenzenediazonium tetrafluoroborate

According to GP B, tetrafluoroboronic acid (48% in water, 3.50 mL, 4.76 g, 26.0 mmol, 2.60 eq), 4-fluoroaniline 69F (950 µL, 1.11 g, 10.0 mmol, 1.00 eq),

sodium nitrite (690 mg, 10.0 mmol, 1.00 eq). The product 34F (1.45 g, 6.91 mmol,

69%) was collected by filtration as a light yellow, crystalline solid.

TS-743 1_{H NMR (399.82 MHz, CD}

3CN):  = 7.63-7.60 (m, 2 H), 8.54-8.61 (m, 2 H)

ppm; 19_{F NMR (376.17 MHz, CD}

3CN):  = -84.61 (s, 1 F), -151.67 (s, 4 F) ppm. The

spectroscopic data matches previously reported data.[13]

6.2.2.5) 4-Nitrobenzenediazonium tetrafluoroborate

According to GP B, tetrafluoroboronic acid (48% in water, 3.50 mL, 4.76 g, 26.0 mmol, 2.60 eq), 4-nitroaniline 69NO2 (1.11 g, 10.0 mmol, 1.00 eq), sodium nitrite

(690 mg, 10.0 mmol, 1.00 eq). The product 34NO2 (1.37 g, 5.78 mmol, 58%) was

collected by filtration as a light yellow, crystalline solid.

TS-594 1_{H NMR (399.82 MHz, DMSO-d}

6):  = 8.72 (d, J = 8.89 Hz, 2 H), 8.93 (d,

J = 8.89, 2 H) ppm; 19_{F NMR (376.17 MHz, DMSO-d}

6):  = -148.32 (s, 4 F) ppm.

The spectroscopic data matches previously reported data.[14]

6.2.2.6) 4-(Trifluoromethyl)benzenediazonium tetrafluoroborate

According to GP B, tetrafluoroboronic acid (48% in water, 3.50 mL, 4.76 g, 26.0 mmol, 2.60 eq), 4-(trifluoromethyl)aniline 69CF3 (1.26 mL, 1.61 g, 10.0 mmol,

1.00 eq), sodium nitrite (690 mg, 10.0 mmol, 1.00 eq). The product 34CF3 (1.72 g,

6.63 mmol, 66%) was collected by filtration as a light rose, crystalline solid.

TS-732 1_{H NMR (399.82 MHz, CD}

3CN):  = 8.23 (d, J = 8.87 Hz, 2 H), 8.68 (d,

J = 8.42, 2 H) ppm; 19_{F NMR (376.17 MHz, CD}

3CN):  = -64.82 (s, 3 F), -151.69 (s,

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6.2.2.7) 4-Cyanophenyldiazonium tetrafluoroborate

According to GP B, tetrafluoroboronic acid (48% in water, 3.50 mL, 4.76 g, 26.0 mmol, 2.60 eq), 4-cyanoaniline 69CN (1.18 g, 10.0 mmol, 1.00 eq), sodium

nitrite (690 mg, 10.0 mmol, 1.00 eq). The product 34CN (1.56 g, 7.17 mmol, 72%)

was collected by filtration as a light yellow, crystalline solid.

TS-731 1_{H NMR (399.82 MHz, (CD}

3)2SO):  = 8.44-8.48 (m, 2 H), 8.81-8.86 (m,

2 H) ppm; 19_{F NMR (376.17 MHz, (CD}

3)2SO):  = -148.21 - -148.29 (m, 4 F) ppm;

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6.2.3) Optimization of Gold-Catalyzed Reactions

6.2.3.1) General Procedure for Reaction Screening, Arylated Benzofuran

The formation of substituted benzofuran 37Me,H was determined by GC MS analysis according

to the following procedure using hexamethylbenzene as internal standard.

Base (200 µmol), diazonium salt (200 µmol) and hexamethylbenzene (100 µmol) were dissolved in 500 µL stock solution of alkyne 25Me,H (200 µmol/mL), 100 µL of a stock solution

of catalyst (10.0 µmol/mL in dichloromethane) and 400 µL addition solvent were added. The mixture was stirred at room temperature under irradiation with blue LED (450 nm) for two hours. The mixture was filled up to 5.00 mL and an aliquot was taken for GC MS analysis. The yields were determined with internal standard and the response factor was determined with an external five-point calibration curve. All reactions were carried out in duplicate and the averages are given unless specified.

Table S 1: Reaction screening for the formation of 37Me,H under irradiation with blue LED.

Entry Catalyst

Base

Yield 37Me,H [%] Irradiation at 450 nm

Solvent MeCN MeCN MeCN

A B Average 1 Ph 3PAuCl NaHCO3 44(a) ₄₈(a) 46 (b) TS-634-A 2 Ph3PAuNTf2 NaHCO3 55(a) ₅₃(a) 54 (c) TS-634-C 3 Ph3PAuCl DTBP 4 4 4 TS-659-A 4 Ph3PAuNTf2 DTBP 8 13 11 TS-676-A+B (a) Full conversion of starting material. (b) Average yield side product 41Me: 7%. (c) Average yield side product 41Me: 25%.

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6.2.3.2) General Procedure for Reaction Screening, Azobenzofuran

The formation of azobenzofuran 32Me,H was determined and quantified by 1H NMR

spectroscopy according to the following procedure using benzylacetate as internal standard. Base (100 µmol) and diazonium salt (100 µmol) were dissolved in 100 µL of a stock solution of catalyst (25.0 µmol/mL in dichloromethane) and molecular sieves (3 Å) was added. 400 µL stock solution of alkyne 25Me (125 µmol/mL) was added and the mixture was stirred for

24 hours at room temperature. The solvents were evaporated and the crude product was dried on the Schlenk line. The solid was dissolved in 600 µL CDCl3 and treated with 7.00 µL of

benzylacetate. The yields were determined with 1_{H NMR spectroscopy. All reactions were}

carried out in duplicate and the averages are given unless specified. Table S 2: Reaction screening for the formation of 32Me,H without irradiation.

Entry Catalyst Base Yield 32Me,H [%] No irradiation Solvent CH2Cl2 MeCN A B Average A B Average 1 Ph3PAuCl 2.00 eq NaHCO3 5 5 5 TS-644-G 6 9 7 TS-644-A 2 Ph3PAuNTf2 2.00 eq NaHCO3 22(a) ₂₃(a) 22 TS-644-I 12 10 11 TS-644-C 3 Ph3PAuCl 2.00 eq DTBP Not obs. Not obs. Not obs. TS-663-D Not obs. Not obs. Not obs. TS-663-A 4 Ph 3PAuNTf2 2.00 eq DTBP 15 23 19 TS-663-E 21 26 23 TS-663-B 5 IMesAuNTf2 2.00 eq NaHCO3 10(a) ₁₀(a) 10 TS-644-K 20 25 22 TS-644-E 6 IMesAuNTf2 2.00 eq DTBP 66 70 68 TS-663-F 16 19 17 TS-663-C 7 IMesAuNTf2 1.20 eq DTBP 59 (b) ₆₇(b) 63 TS-658 - - - 8 IMesAuNTf2 1.20 eq DTBP 64(c) TS-677-A 67(d) TS-677-B - - - -

(a) Full conversion of starting material. (b) Full conversion of starting material after 48 hours. (c) Single run, 150 µmol (3 eq) 34H were used. (d) Single run, 200 µmol (4 eq) 34H were used.

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6.2.4) Control Experiments

6.2.4.1) Arylated Benzofuran

Starting material (100 µmol), catalyst (5.00 mol-%), base (200 µmol), diazonium salt 34H (200 µmol) and hexamethylbenzene (100 µmol) were dissolved in 1.00 mL

acetonitrile. The mixture was stirred at room temperature under irradiation with blue LED (450 nm) for two hours. The mixture was filled up to 5.00 mL and an aliquot was taken for GC MS analysis. The yields were determined by internal standard and the response factor was determined with an external five-point calibration curve.

6.2.4.2) Azo compound

Starting material (50.0 µmol), base (100 µmol) and diazonium salt 34H (100 µmol) were

dissolved in 100 µL of a stock solution of catalyst (25.0 µmol/mL in dichloromethane) and molecular sieves (3 Å) were added. 400 µL Dichloromethane was added and the mixture was stirred for 24 hours at room temperature. The solvents were evaporated and the crude product was dried at the Schlenk line. The solid was recorded in 600 µL CDCl3 and treated with

7.00 µL benzylacetate. The yields were determined with 1_{H NMR spectroscopy.}

6.2.4.3) (E)-4-(Phenyldiazenyl)-2-(p-tolylethynyl)phenol

According to GP C, 2-(p-tolylethynyl)phenol 25Me (52.2 mg,

250 µmol, 1.00 eq) and 2,6-ditertbutylpyridine (113 µL, 95.7 mg, 500 µmol, 2.00 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. Benzenediazonium tetrafluoroborate 34H (96.2 mg,

501 µmol, 2.00 eq) was added and the mixture was stirred at room temperature for 19 days and stopped. The mixture was evaporated onto Celite®_{and purification by flash column chromatography (SiO}

2, PE/EA,

100:1 => 10:1) yielded the product 42 (17.6 mg, 56.3 µmol, 23%) as a moderately pure orange solid.

TS-685 Rf (SiO2, PE/EA, 10:1) = 0.23; 1H NMR (299.95 MHz, CDCl3):  = 2.39 (s, 3 H),

6.17 (bs, 1 H), 7.09-7.14 (m, 1 H), 7.19-7.23 (m, 2 H), 7.43-7.56 (m, 5 H), 7.88-7.94 (m, 3 H), 8.06 (d, J = 2.36 Hz, 1 H) ppm; HR MS(ESI(+)) C21H16N2OH [M+H]+: calcd. 313.13354,

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112

6.2.5) Irradiation Experiments

6.2.5.1) Irradiation of Ph3PAuCl / Ph3PAuNTf2 with p-Tolyldiazonium tetrafluoroborate

TS-715 Ph3PAuCl 7Ph3P,Cl (12.4 mg, 25.1 µmol, 1.00 eq), NaHCO3 (2.1 mg, 25.0 µmol,

1.00 eq) and p-tolyldiazonium tetrafluoroborate 34Me (5.2 mg, 26.8 µmol, 1.07 eq) were

dissolved in 200 µL CD3CN and 4.00 µL tetrachloroethane as internal standard were added.

The solution was irradiated with 405 nm for 144 min and the reaction was monitored every 36 seconds by 1_{H NMR spectroscopy (499.86 MHz, Figure S 1).}

Figure S 1: 1_{H NMR (499.86 MHz, CD}

3CN) of Ph3PAuCl 7Ph3P,Cl with 34Me and NaHCO3 at different times of irradiation, using tetrachloroethane as internal standard.

TS-717 Ph3PAuNTf2 7Ph3P,NTf2 (18.8 mg, 25.4 µmol, 1.02 eq), NaHCO3 (2.1 mg, 25.0 µmol,

1.00 eq) and p-tolyldiazonium tetrafluoroborate 34Me (5.2 mg, 25.2 µmol, 1.01 eq) were

dissolved in 200 µL CD3CN and 4.00 µL tetrachloroethane as internal standard were added.

The solution was irradiated with 405 nm for 144 min and the reaction was monitored every 36 seconds by 1_{H NMR spectroscopy (499.86 MHz, Figure S 2).}

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113 Figure S 2: 1_{H NMR (499.86 MHz, CD}

3CN) of Ph3PAuNTf2 7Ph3P,NTf2 with 34Me and NaHCO3 at different times of irradiation, using tetrachloroethane as internal standard.

TS-748 Ph3PAuNTf2 7Ph3P,NTf2 (18.8 mg, 25.4 µmol, 1.02 eq) and p-tolyldiazonium

tetrafluoroborate 34Me (5.2 mg, 25.2 µmol, 1.01 eq) were dissolved in 200 µL CD3CN and

4.00 µL tetrachloroethane as internal standard were added. The solution was irradiated with 405 nm LED for 144 minutes and the reaction was monitored every 36 seconds by 1_{H NMR}

spectroscopy (499.86 MHz, Figure S 3).

Figure S 3: 1_{H NMR (499.86 MHz, CD}

3CN) of Ph3PAuNTf2 7Ph3P,NTf2 with 34Me at different times of irradiation, using tetrachloroethane as internal standard.

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114

6.2.6) Reactions of Vinyl Gold(I) Complexes

TS-655 Vinyl gold(I) complex 46Me,Ph3P (20.0 mg, 30.0 µmol, 1.00 eq)

was dissolved in 500 µL CD2Cl2 and 2-((4-methylphenyl)

ethynyl)phenol 25Me (6.9 mg, 33.0 µmol, 1.10 eq) was added. The

solution was mixed constantly by a mechanical overhead stirrer for 30 hours. 4.00 µL Benzylacetate was added as internal standard and the 1_{H NMR spectrum was recorded. Product 41}

Me was formed with 16% conversion.

TS-703 Vinyl gold(I) complex 46Me,Ph3P (20.2 mg, 30.3 µmol, 1.01 eq)

was dissolved in 500 µL CD2Cl2 and phenol (3.3 mg, 35.0 µmol,

1.17 eq) was added. The solution was mixed constantly by a mechanical overhead stirrer for 26 hours. 4.00 µL Benzylacetate was added as internal standard and the 1_{H NMR spectrum was recorded.}

Product 41Me was formed with 54% yield.

Vinyl gold(I) complex 46Me,Ph3P was dissolved in 500 µL CD2Cl2 and

benzenediazonium tetrafluoroborate 34H was added. The solution was

mixed constantly by a mechanical overhead stirrer for 24 hours. 4.00 µL Benzylacetate was added as internal standard and the

1_{H NMR spectrum was recorded. Product 32}

Me,H was formed with an

average yield of 46% (double determination).

A) TS-702 46Me,Ph3P (20.0 mg, 30.0 µmol, 1.00 eq), 34H (6.4 mg,

33.5 µmol, 1.12 eq). Yield: 49%.

B) TS-654-II 46Me,Ph3P (20.0 mg, 30.0 µmol, 1.00 eq), 34H (6.3 mg, 33.0 µmol, 1.10 eq).

Yield: 44%.

Vinyl gold(I) complex 46Me,Ph3P was dissolved in 500 µL acetonitrile,

benzenediazonium tetrafluoroborate 34H and hexamethylbenzene

(internal standard) were added. The mixture was irradiated with 450 nm blue LED at room temperature for two hours, analyzed by GC MS and product 37Me,H was formed with an average yield of 65%

(double determination).

A) TS-660 46Me,Ph3P (20.0 mg, 30.0 µmol, 1.00 eq), 34H (6.3 mg,

33.0 µmol, 1.10 eq), HMB (4.7 mg, 29.0 µmol, 0.96 eq). Yield 37Me,H: 69%, yield 41Me : 33%. B) TS-662 46Me,Ph3P (20.1 mg, 30.2 µmol, 1.01 eq), 34H (6.8 mg, 35.5 µmol, 1.20 eq), HMB

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115

6.2.7) Scope of Reaction - Substituted Benzofurans

6.2.7.1) 3-Phenyl-2-(p-tolyl)benzofuran

Ph3PAuCl (9.89 mg, 20.0 µmol, 10.0 mol-%), NaHCO3 (33.6 mg,

400 µmol, 2.00 eq), benzenediazonium tetrafluoroborate 34H

(76.8 mg, 400 µmol, 2.00 eq) and o-(p-tolylethynyl)phenol 25Me

(41.7 mg, 200 µmol, 1.00 eq) were dissolved in 2.00 mL acetonitrile and the mixture was stirred for two hours under blue LED irradiation (450 nm) at room temperature. The mixture was evaporated onto Celite®_{and purification by flash column chromatography (SiO}

2, PE)

yielded the product 37Me,H (36.5 mg, 128 µmol, 64%) as a colorless solid (TS-749 5.00 mol%

catalyst: 29.0 mg, 102 µmol, 51%).

TS-631 Rf (SiO2, PE) = 0.30; 1H NMR (399.82 MHz, CDCl3):  = 2.35 (s, 3 H), 7.13 (d,

J = 7.97 Hz, 2 H), 7.23 (td, J = 7.46 Hz, J = 1.06 Hz, 1 H), 7.29-7.35 (m, 1 H), 7.37-7.57 (m, 9 H) ppm. The spectroscopic data matches previously reported data.[15]

6.2.7.2) 2,3-Di-p-tolylbenzofuran

399 µmol, 1.99 eq), 4-tolyldiazonium tetrafluoroborate 34Me (82.4 mg,

400 µmol, 2.00 eq) and o-(p-tolylethynyl)phenol 25Me (41.7 mg,

200 µmol, 1.00 eq) were dissolved in 1.00 mL acetonitrile and the mixture was stirred for two hours under blue LED irradiation (450 nm) at room temperature. Reaction control by TLC showed starting material left. Therefore the mixture was again irradiated with 450 nm blue LED for two hours at room temperature. The mixture was evaporated onto Celite®_{and purification by flash column chromatography (SiO}

2, PE) yielded

the product 37Me,Me (27.6 mg, 92.5 µmol, 46%) as a colorless solid.

TS-647 Rf (SiO2, PE) = 0.24; 1H NMR (399.82 MHz, CDCl3):  = 2.33 (s, 3 H), 2.42 (s, 3 H),

7.11 (d, J = 7.95 Hz, 2 H), 7.16-7.33 (m, 4 H), 7.34-7.40 (m, 2 H), 7.43-7.49 (m, 1 H), 7.50-7.58 (m, 3 H) ppm. The spectroscopic data matches previously reported data.[16]

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116

6.2.7.3) 3-(4-Fluorophenyl)-2-(p-tolyl)benzofuran

399 µmol, 1.99 eq), 4-fluorobenzenediazonium tetrafluoroborate 34F

(82.4 mg, 393 µmol, 1.96 eq) and o-(p-tolylethynyl)phenol 25Me

2, PE)

yielded the product 37Me,F (31.8 mg, 105 µmol, 53%) as a colorless

solid.

TS-649 Rf (SiO2, PE) = 0.33; 1H NMR (399.82 MHz, CDCl3):  = 2.36 (s, 3 H), 7.12-7.19 (m,

4 H), 7.22-7.26 (m, 1 H), 7.33 (ddd, J = 8.26 Hz, J = 7.20 Hz, J = 1.35 Hz, 1 H), 7.42-7.50 (m, 3 H), 7.50-7.57 (m, 3 H) ppm; 19_{F NMR (376.17 MHz, CDCl}

3):  = -114.45 (s) ppm. The

spectroscopic data matches previously reported data.[17]

6.2.7.4) 3-(4-Nitrophenyl)-2-(p-tolyl)benzofuran

399 µmol, 1.99 eq), 4-nitrobenzenediazonium tetrafluoroborate 34NO2

(94.9 mg, 401 µmol, 1.00 eq) and o-(p-tolylethynyl)-phenol 25Me

2,

PE/EA, 250:1) yielded the product 37Me,NO2 (21.4 mg, 65.0 µmol,

32%) as a yellow, crystalline solid (reaction time 30 min: 22.5 mg, 68.3 µmol, 34%).

TS-652 Rf (SiO2, PE/EA, 100:1) = 0.43; 1H NMR (399.82 MHz, CDCl3):  = 2.37 (s, 3 H),

7.17 (d, J = 7.91 Hz, 2 H), 7.26-7.33 (m, 1 H), 7.37 (ddd, J = 8.14 Hz, J = 7.15 Hz, J = 1.22 Hz, 1 H), 7.50 (dd, J = 7.93 Hz, J = 5.59 Hz, 3 H), 7.58 (dt, J = 8.08 Hz, J = 0.94 Hz, 1 H), 7.65-7.73 (m, 2 H), 8.28-8.35 (m, 2 H) ppm. The spectroscopic data matches previously reported data.[18]

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6.2.7.5) 2-(4-Fluorophenyl)-3-(4-nitrophenyl)benzofuran

400 µmol, 2.00 eq), 2-((4-fluorophenyl) ethynyl)phenol 25F (42.4 mg,

200 µmol, 1.00 eq) and 4-nitrobenzenediazonium tetrafluoro-borate 34NO2 (94.8 mg, 400 µmol, 2.00 eq) were dissolved in 1.00 mL

acetonitrile and the mixture was stirred for 30 minutes under blue LED irradiation (450 nm) at room temperature. The mixture was evaporated onto Celite®_{and purification by flash column chromatography (SiO}

2,

PE/EA, 250:1) yielded the product 37F,NO2 (27.7 mg, 83.1 mmol, 42 %)

as a yellow solid.

TS-753 M.p.: 122 °C; Rf (SiO2, PE/EA, 10:1) = 0.50; IR (ATR): ṽ = 1153, 1160, 1187, 1205,

1227, 1254, 1289, 1296, 1303, 1313, 1369, 1402, 1407, 1413, 1454, 1475, 1489, 1534, 1585, 1601, 1613, 1685, 1692, 1696, 1701, 1793, 1805, 1887, 1943, 1950, 2845, 2924, 3016, 3079, 3101, 3671, 3676, 3744 cm-1_;1_{H NMR (600.13 MHz, CDCl} 3):  = 7.06 (t,J = 8.67 Hz, 2 H), 7.30 (t,J = 7.50 Hz, 1 H), 7.38-7.40 (m, 1 H), 7.51 (d,J = 7.74 Hz, 1 H), 7.57-7.61 (m, 3 H), 7.67-7.69 (m, 2 H), 8.32-8.35 (m, 2 H) ppm; 13_{C NMR (150.90 MHz, CDCl} 3):  = 111.63 (d), 115.43 (s), 116.18 (d, d, J = 21.9 Hz, 2 C), 119.62 (d), 124.62 (d, d, J = 265 Hz, 2 C), 124.54 (d, 2 C), 126.20 (s, d, J = 3.24 Hz, 2 C), 129.07 (s), 129.56 (d, d, J = 8.30 Hz, 2 C), 130.59 (d, 2 C), 140.18 (s), 147.37 (s), 151.19 (s), 154.30 (s, d, J = 251 Hz) ppm; 19_{F NMR} (564.63 MHz, CDCl3):  = - 110.70 (ddd, J = 14.0 Hz, J = 8.29 Hz, J = 5.07 Hz) ppm;

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6.2.8) Scope of Reaction - Substituted Azobenzofurans

6.2.8.1) (E)-1-(2-(4-Methoxyphenyl)benzofuran-3-yl)-2-phenyldiazene

According to GP C, 2-((4-methoxyphenyl)ethynyl)phenol 25OMe

(56.1 mg, 250 µmol, 1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. Benzenediazonium tetrafluoroborate 34H (144 mg, 750 µmol,

3.00 eq) and IMesAuNTf2 (9.77 mg, 12.5 µmol, 5.00 mol-%) were

added and the mixture was stirred at room temperature for 16 hours. The mixture was evaporated onto Celite®_{and purification by flash}

column chromatography (Al2O3, PE/Et2O 200:1) yielded the product 32OMe,H (72.3 mg,

220 µmol, 88%) as an orange, crystalline solid. The structure could be characterized by single-crystal X-ray structure analysis (see 6.7.1.2).

TS-301-B M.p.: 149 °C; Rf (SiO2, PE/EA, 10:1) = 0.40; IR (ATR): ṽ = 686, 745, 770, 783, 836,

934, 1010, 1022, 1075, 1105, 1175, 1205, 1247, 1304, 1411, 1422, 1448, 1502, 1580, 1604, 1742, 1938, 2033, 2839, 2965, 3030, 3065, 3083 cm-1; UV ( = 242 nm in CH 2Cl2): log  = 3.87; 1_{H NMR (300.51 MHz, CDCl} 3):  = 3.92 (s, 3 H), 7.08 (td, J = 9.07 Hz, J = 2.10 Hz, 2 H), 7.33-7.39 (m, 2 H), 7.43-7.47 (m, 1 H), 7.51-7.56 (m, 3 H), 7.93-7.96 (m, 2 H), 8.40 (td, J = 9.07 Hz, J = 2.10 Hz, 2 H), 8.44-8.48 (m, 1 H) ppm; 13_{C NMR (100.66 MHz,} CDCl3):  = 55.59 (q), 111.09 (d), 114.49 (d, 2 C), 121.58 (s), 122.64 (d, 2 C), 122.66 (s), 124.01 (d), 124.81 (d), 125.84 (d), 129.25 (d, 2 C), 130.16 (d), 130.46 (d, 2 C), 133.79 (s), 153.79 (s), 154.01 (s), 157.74 (s), 161.43 (s) ppm; HR MS (DART(+)) C21H17N2O2 [M+H]+: calcd. 329.1276, found 329.1285. 6.2.8.2) (E)-1-(2-(4-Methoxyphenyl)benzofuran-3-yl)-2-(p-tolyl)diazene

According to GP C, IMesAuNTf2 (9.77 mg, 12.5 µmol, 5.00 mol-%)

and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. 2-((4-Methoxyphenyl)ethynyl) phenol 25OMe (56.1 mg, 250 µmol, 1.00 eq) and

4-methylbenzenediazonium tetrafluoroborate 34Me (154 mg,

750 µmol, 3.00 eq) were added and the mixture was stirred at room temperature for 4.5 hours. The mixture was evaporated onto Celite®

and purification by flash column chromatography (SiO2, PE/Et2O

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TS-762 M.p.: 160 °C; Rf (SiO2, PE/EA, 5:1) = 0.65; IR (ATR): ṽ = 601, 609, 629, 639, 648, 661,

668, 682, 689, 709, 742, 758, 783, 818, 829, 836, 854, 876, 891, 933, 966, 1011, 1024, 1074, 1103, 1116, 1141, 1173, 1203, 1249, 1289, 1305, 1347, 1374, 1398, 1423, 1449, 1472, 1497, 1555, 1580, 1603, 1877, 1898, 2036, 2049, 2838, 2852, 2926, 2963, 2990, 3021, 3035, 3058, 3082 cm-1_;1_{H NMR (600.13 MHz, CDCl} 3):  = 2.46 (s, 3 H), 3.92 (s, 3 H), 7.05-7.10 (m, 2 H), 7.31-7.39 (m, 4 H), 7.50-7.54 (m, 1 H), 7.86 (d, J = 7.96 Hz, 2 H), 8.38-8.42 (m, 2 H), 8.46 (dd, J = 7.44 Hz, J = 1.73 Hz, 1 H) ppm; 13_{C NMR (150.92 MHz, CDCl} 3):  = 21.65 (q), 55.58 (q), 111.06 (d), 114.44 (d, 2 C), 121.69 (s), 122.58 (d, 2 C), 122.75 (s), 124.02 (d), 124.70 (d), 125.75 (d), 129.91 (2 C), 130.35 (d, 2 C), 133.67 (s), 140.61 (s), 152.09 (s), 153.76 (s), 157.17 (s), 161.27 (s) ppm; HR MS (ESI(+)) C22H19N2O2 [M+H]+.:

calcd. 343.14410, found 343.14325. The spectroscopic data matches previously reported data.[19]

6.2.8.3) (E)-1-(4-Methoxyphenyl)-2-(2-(4-methoxyphenyl)benzofuran-3-yl)diazene

(56.1 mg, 250 µmol, 1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 1.50 mL dichloromethane and stirred at room temperature for ten minutes. 4-Methoxybenzenediazonium tetrafluoroborate 34OMe (83.2 mg,

375 µmol, 1.50 eq) and IMesAuNTf2 (9.77 mg, 12.5 µmol,

5.00 mol-%) were added and the mixture was stirred at room temperature for 18 hours. Purification by flash column chromatography (SiO2, PE/EA 50:1) yielded the product 32OMe,OMe

(55.2 mg, 154 µmol, 62%) as an orange-yellow, crystalline solid.

TS-215 M.p.: 166 °C; Rf (SiO2, PE/EA, 10:1) = 0.54; IR (ATR): ṽ = 607, 618, 630, 637, 665,

682, 704, 742, 757, 783, 795, 802, 825, 876, 932, 959, 972, 1010, 1025, 1072, 1100, 1116, 1135, 1153, 1173, 1202, 1242, 1291, 1305, 1323, 1349, 1380, 1400, 1422, 1435, 1448, 1472, 1495, 1554, 2031, 2039, 2049, 2834, 2898, 2929, 2961, 3036, 3054, 3080 cm-1_;1_{H NMR} (300.51 MHz, CDCl3):  = 3.92 (s, 6 H), 7.03-7.10 (m, 4 H), 7.30-7.39 (m, 2 H), 7.50-7.53 (m, 1 H), 7.94 (dt, J = 9.02 Hz, J = 2.10 Hz, 2 H), 8.39 (dt, J = 9.08 Hz, J = 2.10 Hz, 2 H), 8.44-8.48 (m, 1 H) ppm; 13_{C NMR (150.92 MHz, CDCl} 3):  = 55.57 (q), 55.74 (q), 111.05 (d), 114.41 (d, 4 C), 121.82 (s), 122.85 (s), 124.01 (d), 124.30 (d, 2 C), 124.58 (d), 125.67 (d), 130.22 (d, 2 C), 133.55 (s), 148.36 (s), 153.74 (s), 156.56 (s), 161.15 (s), 161.49 (s) ppm; HR MS (ESI(+)) C22H19N2O3 [M+H]+.: calcd. 359.13902, found 359.13872. The spectroscopic

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6.2.8.4) (E)-1-(4-Fluorophenyl)-2-(2-(4-methoxyphenyl)benzofuran-3-yl)diazene

(56.1 mg, 250 µmol, 1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. 4-Fluorobenzenediazonium tetrafluoroborate 34F (156 mg,

744 µmol, 2.98 eq) and IMesAuNTf2 (9.8 mg, 12.5 µmol,

5.00 mol-%) were added and the mixture was stirred at room temperature for 3.5 hours. The mixture was evaporated onto Celite®

and purification by flash column chromatography (SiO2, PE/Et2O

200:1) yielded the product 32OMe,F (68.4 mg, 197 µmol, 79%) as an orange, crystalline solid.

TS-761 M.p.: 144 °C; Rf (SiO2, PE/EA, 5:1) = 0.69; IR (ATR): ṽ = 1176, 1185, 1192, 1208,

1224, 1249, 1285, 1293, 1306, 1338, 1348, 1378, 1401, 1423, 1436, 1449, 1474, 1505, 1556, 1561, 1566, 1582, 1591, 1605, 1773, 1778, 1882, 2034, 2160, 2556, 2838, 2900, 2934, 2965, 3020, 3036, 3049, 3059, 3083, 3744, 3854 cm-1_;1_{H NMR (600.13 MHz, CDCl} 3):  = 3.92 (s, 3 H), 7.06-7.09 (m, 2 H), 7.20-7.24 (m, 2 H), 7.36 (dtd, J = 16.4 MHz, J = 7.28 Hz, J = 1.38 Hz, 2 H), 7.51-7.54 (m, 1 H), 7.91-7.97 (m, 2 H), 8.36-8.39 (m, 2 H), 8.41-8.44 (m, 1 H) ppm; 13_{C NMR (150.92 MHz, CDCl} 3):  = 55.59 (q), 111.13 (d), 114.50 (d, 2 C), 116.19 (d, d, J = 22.6 Hz, 2 C), 121.53 (s), 122.58 (s), 123.92 (d), 124.39 (d, d, J = 9.06 Hz, 2 C), 124.81 (d), 125.90 (d), 130.43 (d, 2 C), 133.63 (s), 150.54 (s, d, J = 3.02 Hz), 153.78 (s), 157.74 (s), 161.46 (s), 163.94 (s, d, J = 250 Hz) ppm; 19_{F NMR (564.63 MHz, CDCl} 3):  = -110.90 - -110.95 (m, 1 F) ppm; HR MS (ESI(+)) C21H16N2O2F [M+H]+.: calcd. 347.11903, found 347.11894. 6.2.8.5) (E)-1-Phenyl-2-(2-(p-tolyl)benzofuran-3-yl)diazene

According to GP C, 2-(p-tolylethynyl)phenol 25Me (52.1 mg, 250 µmol,

1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. Benzenediazonium tetrafluoroborate 34H (144 mg, 750 µmol, 3.00 eq) and IMesAuNTf2

(9.77 mg, 12.5 µmol, 5.00 mol-%) were added and the mixture was stirred at room temperature for 27 hours. The mixture was evaporated onto Celite®_{and purification by flash column chromatography (Al}

2O3,

PE/Et2O, 200:1) yielded the desired product 32Me,H (60.9 mg, 195 µmol, 78%) as an orange,

crystalline solid. The structure could be characterized by single-crystal X-ray structure analysis (see 6.7.1.1).

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TS-283-B M.p.: 137 °C;Rf (SiO2, PE/EA, 10:1) = 0.73; IR (ATR): ṽ = 609, 617, 634, 670, 689,

716, 743, 774, 825, 874, 934, 1017, 1077, 1145, 1201, 1252, 1289, 1304, 1347, 1372, 1410, 1450, 1475, 1504, 1552, 1577, 1608, 1784, 1898, 1921, 2855, 2924, 3032, 3065 cm-1_; UV ( = 295 nm in CH2Cl2): log  = 4.43; 1H NMR (300.51 MHz, CDCl3):  = 2.46 (bs, 3 H), 7.34-7.41 (m, 4 H), 7.44-7.48 (m, 1 H), 7.53-7.57 (m, 3 H), 7.95-7.97 (m, 2 H), 8.32-8.34 (m, 2 H), 8.46-8.48 (m, 1 H) ppm; 13_{C NMR (100.66 MHz, CDCl} 3):  = 21.73 (q), 111.22 (d), 121.47 (s), 122.71 (d, 2 C), 124.13 (d), 124.85 (d), 126.03 (d), 127.17 (s), 128.76 (d, 2 C), 129.26 (d, 2 C), 129.65 (d, 2 C), 130.30 (d), 134.32 (s), 140.52 (s), 153.89 (s), 153.96 (s), 157.77 (s) ppm; HR MS (EI(+), 70 eV) C21H16N2O [M]+: calcd. 312.12571, found 312.12462.

6.2.8.6) (E)-1-(p-Tolyl)-2-(2-(p-tolyl)benzofuran-3-yl)diazene

1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. p-Tolyldiazonium tetrafluoroborate 34Me (154 mg, 750 µmol, 3.00 eq) and IMesAuNTf2

2O3,

PE/Et2O, 200:1) yielded the desired product 32Me,Me (56.3 mg,

172 µmol, 69%) as an orange, crystalline solid.

TS-285-C M.p.: 135 °C;Rf (SiO2, PE/EA, 10:1) = 0.66; IR (ATR): ṽ = 609, 662, 741, 757, 819,

875, 934, 1011, 1021, 1036, 1075, 1104, 1141, 1160, 1186, 1203, 1253, 1289, 1372, 1449, 1474, 1504, 1552, 1577, 1601, 2919, 3037, 3059, 3081 cm-1; UV ( = 298 nm in CH 2Cl2): log  = 4.59; 1_{H NMR (300.51 MHz, CDCl} 3):  = 2.46 (bs, 6 H), 7.32-7.40 (m, 6 H), 7.52-7.55 (m, 1 H), 7.87 (td, J = 8.29 Hz, J = 1.82 Hz, 2 H), 8.32 (td, J = 8.29 Hz, J = 1.82 Hz, 2 H), 8.45-8.48 (m, 1 H) ppm; 13_{C NMR (100.66 MHz, CDCl} 3):  = 21.65 (q), 21.72 (q), 111.17 (d), 121.61 (s), 122.67 (d, 2 C), 124.13 (d), 124.74 (d), 125.95 (d), 127.29 (s), 128.68 (d, 2 C), 129.62 (d, 2 C), 129.93 (d, 2 C), 134.24 (s), 140.35 (s), 140.77 (s), 152.10 (s), 153.89 (s), 157.23 (s) ppm; HR MS (EI(+), 70 eV) C22H18N2O [M]+: calcd. 326.14136, found 326.13978. 6.2.8.7) (E)-1-(4-Methoxyphenyl)-2-(2-(p-tolyl)benzofuran-3-yl)diazene

1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. p-Methoxybenzenediazonium tetrafluoroborate 34OMe (166 mg, 750 µmol, 3.00 eq) and IMesAuNTf2

2O3,

PE/Et2O, 100:1) yielded the desired product 32Me,OMe (33.0 mg,

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122

TS-675-CII M.p.: 144 °C; Rf (SiO2, PE/EA, 10:1) = 0.57; IR (ATR): ṽ = 608, 618, 639, 661, 715,

744, 758, 799, 820, 836, 933, 970, 1007, 1023, 1075, 1101, 1135, 1155, 1182, 1202, 1245, 1286, 1292, 1310, 1320, 1339, 1346, 1375, 1400, 1413, 1436, 1446, 1458, 1472, 1496, 1551, 1578, 1601, 2835, 2852, 2921, 2960, 3002, 3022, 3045, 3077 cm-1_;1_{H NMR (600.13 MHz,} CDCl3):  = 2.46 (s, 3 H), 3.92 (s, 3 H), 7.01-7.08 (m, 2 H), 7.31-7.39 (m, 4 H), 7.53 (dt, J = 8.19 Hz, J = 0.84 Hz, 1 H), 7.91-7.98 (m, 2 H), 8.29-8.34 (m, 2 H), 8.44-8.48 (m, 1 H) ppm; 13_{C NMR (150.91 MHz, CDCl} 3):  = 21.71 (q), 55.75 (q), 111.17 (d), 114.44 (d, 2 C), 121.74 (s), 124.14 (d), 124.40 (d, 2 C), 124.63 (d), 125.87 (d), 127.37 (s), 128.57 (d, 2 C), 129.60 (d, 2 C), 134.13 (s), 140.17 (s), 148.38 (s), 153.87 (s), 156.62 (s), 161.62 (s) ppm; HR MS (ESI(+)) C22H19N2O2 [M+H]+: calcd. 343.14410, found 343.14438.

6.2.8.8) (E)-1-(4-Fluorophenyl)-2-(2-(p-tolyl)benzofuran-3-yl)diazene

1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. p-Fluorobenzenediazonium tetrafluoroborate 34F (157 mg, 750 µmol, 3.00 eq) and IMesAuNTf2

2O3,

PE/Et2O, 200:1) yielded the desired product 32Me,F (48.7 mg,

147 µmol, 59%) as an orange, crystalline solid.

TS-286-C M.p.: 156 °C; Rf (SiO2, PE/EA, 10:1) = 0.66; IR (ATR): ṽ = 609, 636, 663, 746, 820,

839, 875, 935, 1007, 1023, 1076, 1090, 1105, 1135, 1151, 1192, 1205, 1226, 1287, 1342, 1375, 1434, 1449, 1474, 1494, 1553, 1578, 1591, 1738, 1897, 2921, 3037 cm-1_; UV ( = 296 nm in CH2Cl2): log  = 4.40; 1H NMR (300.51 MHz, CDCl3):  = 2.46 (bs, 3 H), 7.19-7.25 (m, 2 H), 7.33-7.41 (m, 4 H), 7.53-7.56 (m, 1 H), 7.93-7.98 (m, 2 H), 8.43 (td, J = 8.37 Hz, J = 1.60 Hz, 2 H), 8.42-8.44 (m, 1 H) ppm; 13_{C NMR (100.66 MHz, CDCl} 3):  = 21.73 (q), 111.25 (d), 116.09 (d), 116.31 (d), 121.42 (s), 124.04 (d), 124.45 (d), 124.70 (d, d, J = 40.6 Hz, 2 C), 126.10 (d), 127.12 (s), 128.74 (d, 2 C), 129.68 (d, 2 C), 134.17 (s), 140.61 (s), 150.52 (s, d, J = 3.17 Hz), 153.89 (s), 157.80 (s), 164.04 (s, d, J = 251 Hz) ppm; 19_{F NMR (282.76 MHz, CDCl} 3):  = -110.70 (s) ppm; HR MS (EI(+), 70 eV) C21H15FN2O [M]+: calcd. 330.11629, found 330.11684.

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123

6.2.8.9) (E)-1-(2-(p-Tolyl)benzofuran-3-yl)-2-(4-(trifluoromethyl)phenyl)diazene

According to GP C, 2-((4-methylphenyl)ethynyl)phenol 25Me (33.0 mg,

158 µmol, 1.00 eq) and 2,6-ditertbutylpyridine (43.0 µL, 36.4 mg, 190 µmol, 1.20 eq) were dissolved in 1.50 mL dichloromethane and stirred at room temperature for ten minutes. 4-(Trifluoromethyl)benzenediazonium tetrafluoroborate 34CF3

(124 mg, 475 µmol, 3.00 eq) and IMesAuNTf2 (6.2 mg, 7.92 µmol,

5.00 mol-%) were added and the mixture was stirred at room temperature for 41 hours. The mixture was evaporated onto Celite®

and purification by flash column chromatography (SiO2, PE/EA 500:1)

yielded the product 32Me,CF3 (8.9 mg, 23.4 µmol, 15%) as an orange, crystalline solid.

TS-806 Rf (SiO2, PE/EA, 200:1) = 0.63; IR (ATR): ṽ = 667, 676, 717, 745, 821, 847, 935, 969,

1010, 1065, 1077, 1100, 1167, 1186, 1202, 1253, 1290, 1323, 1378, 1395, 1430, 1449, 1473, 1503, 1551, 1577, 1611, 1677, 2852, 2923 cm-1_;1_{H NMR (600.13 MHz, CDCl} 3):  = 2.47 (s, 3 H), 7.35-7.44 (m, 4 H), 7.54-7.58 (m, 1 H), 7.80 (d, J = 8.17 Hz, 2 H), 8.02 (d, J = 8.19 Hz, 2 H), 8.31 (d, J = 8.04 Hz, 2 H), 8.43 (dd, J = 7.59 Hz, J = 1.58 Hz, 1 H) ppm; 13_{C NMR} (150.92 MHz, CDCl3):  = 21.78 (q), 111.32 (d), 121.04 (s), 122.79 (d, 2 C), 123.32 (s), 124.02 (d), 125.13 (d), 126.36 (d), 126.46 (d, q, J = 3.81 Hz, 2 C), 126.82 (s), 128.94 (d, 2 C), 129.76 (d, 2 C), 131.41 (s, q, J = 32.4 Hz), 134.62 (s), 141.11 (s), 153.90 (s), 155.81 (s), 159.15 (s) ppm; 19_{F NMR (564.63 MHz, CDCl} 3):  = -62.37 (s, 3 F) ppm; HR MS (ESI(+)) C22H16N2O2F3 [M+H]+.: calcd. 381.12092, found 381.12066. 6.2.8.10) (E)-1-Phenyl-2-(2-phenylbenzofuran-3-yl)diazene

According to GP C, 2-(phenylethynyl)phenol 25H (48.6 mg, 250 µmol,

1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. Benzenediazonium tetrafluoroborate 34H

(144 mg, 750 µmol, 3.00 eq) and IMesAuNTf2 (9.77 mg, 12.5 µmol,

5.00 mol-%) were added and the mixture was stirred at room temperature for 168 hours. The mixture was evaporated onto Celite®

and purification by flash column chromatography (Al2O3, PE/Et2O,

200:1) yielded the desired product 32H,H (16.5 mg, 55.3 µmol, 22%) as

an orange, crystalline solid.

934, 1029, 1070, 1109, 1141, 1204, 1288, 1343, 1372, 1412, 1439, 1455, 1475, 1490, 1552 cm-1; UV ( = 294 nm in CH 2Cl2): log  = 4.36; 1H NMR (300.51 MHz, CDCl3):  = 7.39 (dt, J = 7.51 Hz, J = 1.92 Hz, 2 H), 7.45-7.51 (m, 2 H), 7.54-7.58 (m, 5 H), 7.96-7.99 (m, 2 H), 8.42-8.49 (m, 3 H) ppm; 13_{C NMR (100.66 MHz, CDCl} 3):  = 111.28 (d), 121.38 (s), 122.76 (d, 2 C), 124.26 (d), 124.93 (d), 126.23 (d), 128.80 (d, 2 C), 128.86 (d, 2 C), 129.29 (d, 2 C), 129.94 (s), 130.08 (d), 130.47 (d), 134.72 (s), 153.91 (s), 153.98 (s), 157.30 (s) ppm; HR MS (EI(+), 70 eV) C20H14N2O [M]+: calcd. 298.11006, found 298.11001.

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124

6.2.8.11) (E)-1-(2-Phenylbenzofuran-3-yl)-2-(p-tolyl)diazene

1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. p-Methylbenzenediazonium tetrafluoroborate 34Me (154 mg, 750 µmol, 3.00 eq) and IMesAuNTf2

2O3,

PE/Et2O, 200:1) yielded the desired product 32H,Me (23.8 mg,

76.2 µmol, 31%) as an orange, crystalline solid. The structure could be characterized by single-crystal X-ray structure analysis (see 6.7.1.3).

TS-277-C M.p.: 120 °C, Rf (SiO2, PE/EA, 10:1) = 0.75; IR (ATR): ṽ = 686, 744, 772, 823, 935,

1013, 1078, 1111, 1143, 1205, 1254, 1289, 1345, 1374, 1399, 1440, 1454, 1474, 1491, 1556, 1580, 1604, 1737, 1792, 1903, 1935, 1951, 1971, 2855, 2922, 3036, 3055 cm-1_; UV ( = 296 nm): log  = 4.40; 1_{H NMR (400.33 MHz, CDCl} 3):  = 2.46 (s, 3 H), 7.34-7.42 (m, 4 H), 7.45-7.50 (m, 1 H), 7.53-7.57 (m, 3 H), 7.86-7.89 (m, 2 H), 8.42-8.49 (m, 3 H) ppm; 13_{C NMR (100.66 MHz, CDCl} 3):  = 21.66 (q), 111.25 (d), 121.52 (s), 122.72 (d, 2 C), 124.29 (d), 124.82 (d), 126.14 (d), 128.72 (d, 2 C), 128.83 (d, 2 C), 129.93 (d), 129.95 (d, 2 C), 130.05 (s), 134.66 (s), 140.97 (s), 152.05 (s), 153.97 (s), 156.75 (s) ppm; HR MS (EI(+), 70 eV) C21H16N2O [M]+: calcd. 312.12571, found 312.12529; Elemental Anal. calculated for

C21H16N2O [%]: C, 80.75; H, 5.16; N, 8.97; O, 5.12. Found: C, 79.93; H, 5.70; N, 7.92.

6.2.8.12) (E)-1-(4-Methoxyphenyl)-2-(2-phenylbenzofuran-3-yl)diazene

1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. 4-Methoxybenzenediazonium tetrafluoroborate 34OMe (166 mg, 750 µmol, 3.00 eq) and IMesAuNTf2

(9.77 mg, 12.5 µmol, 5.00 mol-%) were added and the mixture was stirred at room temperature for 168 hours. The mixture was evaporated onto Celite®_{and purification by flash column chromatography (SiO}

2,

PE/EA 200:1) yielded the product 32H,OMe (16.6 mg, 50.6 µmol, 20%)

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125

TS-276-B/182-A M.p.: 120 °C; Rf (SiO2, PE/EA, 10:1) = 0.51; IR (ATR): ṽ = 3064, 2926, 2853,

1731, 1672, 1598, 1498, 1446, 1376, 1253, 1206, 1139, 1110, 1074, 1033, 937, 838, 753, 693, 643 cm-1_;_{UV ( = 304 nm): log  = 4.29;}1_{H NMR (300.51 MHz, CDCl} 3):  = 3.92 (bs, 3 H), 7.06 (td, J = 15.3 Hz, J = 2.14 Hz, 2 H), 7.33-7.41 (m, 2 H), 7.44-7.49 (m, 1 H), 7.52-7.57 (m, 3 H), 7.96 (td, J = 9.05 Hz, J = 2.14 Hz, 2 H), 8.41-8.44 (m, 2 H), 8.46-8.48 (m, 1 H) ppm; 13_{C NMR (100.66 MHz, CDCl} 3):  = 55.77 (q), 111.25 (d), 114.49 (d, 2 C), 121.67 (s), 124.29 (d), 124.72 (d), 124.49 (d, 2 C), 126.08 (d), 128.62 (d, 2 C), 128.82 (d, 2 C), 129.80 (d), 130.17 (s), 134.58 (s), 148.35 (s), 153.97 (s), 156.16 (s), 161.77 (s) ppm; HR MS (ESI(+)) C21H17N2O2 [M+H]+: calcd. 329.1290, found 329.1291; Elemental Anal.

calculated for C21H16N2O2 [%]: C, 76.81; H, 4.91; N, 8.53; O, 9.74. Found: C, 76.81; H, 5.12;

N, 8.03.

6.2.8.13) (E)-1-(4-Fluorophenyl)-2-(2-phenylbenzofuran-3-yl)diazene

1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. 4-Fluorobenzenediazonium tetrafluoroborate 34F (157 mg, 750 µmol, 3.00 eq) and IMesAuNTf2

2O3,

PE/EA 200:1) yielded the product 32H,F (9.20 mg, 29.1 µmol, 12%) as

a moderately pure, orange, crystalline solid.

TS-278-B Rf (SiO2, PE/EA, 10:1) = 0.78; 1H NMR (300.51 MHz, CDCl3):  = 7.20-7.25 (m, 1 H), 7.33-7.44 (m, 2 H), 7.45-7.61 (m, 5 H), 7.93-8.02 (m, 2 H), 8.38-8.47 (m, 3 H) ppm; 19_{F NMR (282.76 MHz, CDCl} 3):  = -110.40 (s) ppm. 6.2.8.14) (E)-1-(2-(4-Fluorophenyl)benzofuran-3-yl)-2-phenyldiazene According to GP C, 2-((4-fluorophenyl)ethynyl)phenol 25F (53.1 mg,

250 µmol, 1.00 eq) and 2,6-ditertbutylpyridine (67.4 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. Benzenediazonium tetrafluoroborate 34H (144 mg, 750 µmol, 3.00 eq) and IMesAuNTf2

(9.77 mg, 12.5 µmol, 5.00 mol-%) were added and the mixture was stirred at room temperature for 21 days. The mixture was evaporated onto Celite®_{and purification by flash column chromatography (Al}

2O3,

PE/Et2O, 200:1) yielded the desired product 32F,H (26.0 mg, 82.2 µmol,

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126

936, 1017, 1076, 1102, 1160, 1201, 1232, 1286, 1370, 1411, 1450, 1477, 1500, 1556, 1598 cm-1; UV ( = 292 nm in CH 2Cl2): log  = 4.42; 1H NMR (300.51 MHz, CDCl3):  = 7.24-7.26 (m, 2 H), 7.37 (dt, J = 7.56 Hz, J = 0.93 Hz, 1 H), 7.40 (dt, J = 7.56 Hz, J = 0.93 Hz, 1 H), 7.46-7.49 (m, 1 H), 7.54-7.57 (m, 3 H), 7.94-7.96 (m, 2 H), 8.43-8.48 (m, 3 H) ppm; 13_{C NMR (150.93 MHz, CDCl} 3):  = 111.24 (d), 116.12 (d, d, J = 22.0 Hz, 2 C), 121.29 (s), 122.70 (d, 2 C), 124.22 (d), 125.02 (d), 126.22 (s, d, J = 22.0 Hz), 126.28 (d), 129.23 (d, 2 C), 130.56 (d), 130.77 (d, d, J = 8.45 Hz, 2 C), 134.40 (s, d, J = 1.31 Hz), 153.83 (s, d, J = 7.12 Hz, 2 C), 156.35 (s), 164.03 (s, d, J = 252 Hz) ppm; 19_{F NMR} (282.76 MHz, CDCl3):  = -109.80 (s) ppm; HR MS (EI(+), 70 eV) C20H13N2OF [M]+: calcd. 316.10064, found 316.10073. 6.2.8.15) (E)-1-(2-(4-Fluorophenyl)benzofuran-3-yl)-2-phenyldiazene According to GP C, 2-((4-fluorophenyl)ethynyl)phenol 25F (53.1 mg,

250 µmol, 1.00 eq) and 2,6-ditertbutylpyridine (67.5 µL, 57.4 mg, 300 µmol, 1.20 eq) were dissolved in 2.00 mL dichloromethane and stirred at room temperature for ten minutes. 4-Methoxybenzenediazonium tetrafluoroborate 34OMe (166 mg,

750 µmol, 3.00 eq) and IMesAuNTf2 (9.77 mg, 12.5 µmol, 5.00 mol-%)

were added and the mixture was stirred at room temperature for 21 days. The mixture was evaporated onto Celite®_{and purification by}

flash column chromatography (Al2O3, PE/Et2O, 100:1 -> 50:1) yielded

the desired product 32F,OMe (27.4 mg, 79.1 µmol, 32%) as an orange, crystalline solid.

666, 678, 706, 743, 759, 791, 803, 821, 836, 875, 934, 961, 1012, 1025, 1075, 1101, 1140, 1154, 1185, 1203, 1221, 1230, 1250, 1288, 1315, 1341, 1373, 1413, 1437, 1449, 1462, 1475, 1496, 1557, 1580, 1600, 1649, 1680, 1712, 1726, 1771, 1823, 1868, 1876, 1902, 2024, 2040, 2562, 2836, 2851, 2874, 2900, 2916, 2940, 2957, 3027, 3081, 3102 cm-1_;1_{H NMR} (600.13 MHz, CDCl3):  = 3.92 (s, 3 H), 7.05-7.07 (m, 2 H), 7.21-7.25 (m, 2 H), 7.35 (td, J = 7.35 Hz, J = 1.17 Hz, 1 H), 7.39 (td, J = 7.88 Hz, J = 1.57 Hz, 1 H), 7.53 (dt, J = 8.25 Hz, J = 0.83 Hz, 1 H), 7.92-7.96 (m, 2 H), 8.40-8.44 (m, 2 H), 8.45-8.47 (m, 1 H) ppm; 13_{C NMR} (150.92 MHz, CDCl3):  = 55.76 (q), 111.20 (d), 114.50 (d, 2 C), 116.03 (d, d, J = 21.8 Hz, 2 C), 121.59 (s), 124.26 (d), 124.44 (d, 2 C), 124.79 (d), 126.11 (d), 126.46 (s, d, J = 3.02 Hz), 130.55 (d, d, J = 8.50 Hz, 2 C), 134.26 (s, d, J = 1.51 Hz), 148.25 (s), 153.86 (s) 155.21 (s), 161.82 (s), 163.85 (s, d, J = 251 Hz) ppm; 19_{F NMR (564.63 MHz, CDCl} 3):  = -110.32 (m, 1 F) ppm; HR MS (ESI(+)) C21H16N2O2F [M+H]+.: calcd. 347.11903, found 347.11841.

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127

6.3)

Experimental Section, Chapter 3

6.3.1) Synthesis of Gold(I) Complexes

6.3.1.1) (2-Phenylbenzofuran-3-yl)(triphenyl-5_{-phosphanyl) gold(I)}

According to GP D, Ph3PAuCl (146 mg, 294 µmol, 1.00 eq) and AgOTs

(82.1 mg, 294 µmol, 1.00 eq) were dissolved in 50.0 mL THF and stirred for one hour at room temperature. Triethylamine (297 µL, 208 mg, 2.08 mmol, 7.00 eq) and 2-(phenylethynyl)phenol 25H

(58.3 mg, 300 µmol, 1.02 eq) were added and the mixture was stirred for 46 hours. Recrystallization yielded the product 46H,Ph3P (155 mg,

284 µmol, 81%) as a light yellow, crystalline solid. The structure could be characterized by single-crystal X-ray structure analysis (see 6.7.1.5).

TS-688 M.p.: decomp > 179 °C; IR (ATR): ṽ = 634, 666, 688, 710, 736, 749, 765, 812, 847, 886, 915, 970, 998, 1008, 1017, 1028, 1039, 1069, 1100, 1142, 1157, 1181, 1199, 1251, 1308, 1330, 1388, 1434, 1448, 1465, 1479, 3014, 3032, 3047, 3066 cm-1_;1_{H NMR} (600.13 MHz, CD2Cl2):  = 7.14 (dd,J = 7.38 Hz, J = 1.09 Hz, 1 H), 7.19 (dd, J = 7.59 Hz, J = 1.41 Hz, 1 H), 7.25-7.30 (m, 1 H), 7.31-7.35 (m, 2 H), 7.49 (d, J = 8.27 Hz, 1 H), 7.50-7.61 (m, 9 H), 7.65-7.70 (m, 6 H), 7.78-7.80 (m, 1H), 8.40 (dt, J = 8.40 Hz, J = 1.32 Hz, 2 H) ppm; 13_{C NMR (150.92 MHz, CD} 2Cl2):  = 110.65 (d), 121.83 (d), 123.74 (d), 124.95 (d), 125.71 (d, 2 C), 127.57 (d), 128.54 (d, 2 C), 129.56 (d, 3 C), 129.64 (d, 3 C), 130.88 (s), 131.23 (s), 131.83 (d, d, J = 2.43 Hz, 3 C), 134.48 (s), 134.70 (d, 3 C), 134.79 (d, 3 C), 139.63 (s, 3 C), 155.49 (s), 162.21 (s) ppm; 31_{P NMR} _{(242.92 MHz,} _CD 2Cl2):

 = 45.18 (s) ppm; HR MS (DART(+)) C32H25AuOP [M+H]+: calcd. 653.1303, found 653.1302.

6.3.1.2) (2-(p-Tolyl)benzofuran-3-yl)(triphenyl-5_{-phosphanyl) gold(I)}

According to GP D, Ph3PAuCl (146 mg, 294 µmol, 1.00 eq) and

AgOTs (82.1 mg, 294 µmol, 1.00 eq) were dissolved in 50.0 mL THF and stirred for one hour at room temperature. Triethylamine (297µL, 208 mg, 2.08 mmol, 7.00 eq) and 2-((4-methylphenyl) ethynyl)phenol 25Me (62.5 mg, 300 µmol, 1.02 eq) were added and the

mixture was stirred for 19 hours. The mixture was filtered through a pad of neutral Al2O3 and evaporated at room temperature.

Recrystallization yielded the product 46Me,Ph3P (166 mg, 249 µmol,

85%) as a colorless, crystalline solid. The structure could be characterized by single-crystal X-ray structure analysis (see 6.7.1.4).

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128 TS-686 M.p.: decomp >181 °C; IR (ATR): ṽ = 693, 710, 741, 748, 822, 886, 920, 969, 997, 1012, 1029, 1069, 1100, 1158, 1180, 1200, 1251, 1264, 1281, 1308, 1331, 1338, 1433, 1447, 1465, 1479, 1490, 2918, 3014, 3046, 3067 cm-1_;1_{H NMR (600.13 MHz, CD} 2Cl2):  = 2.37 (s, 3 H), 7.09-7.19 (m, 4 H), 7.46 (d, J = 7.95 Hz, 1 H), 7.49-7.59 (m, 9 H), 7.64-7.70 (m, 6 H), 7.73-7.79 (m, 1 H), 8.33 (d, J = 7.97 Hz, 2 H) ppm; 13_{C NMR (150.92 MHz, CD} 2Cl2):  = 21.42 (q), 110.57 (d), 121.79 (d), 123.50 (d), 124.78 (d), 125.71 (d, 2 C), 129.25 (d, 2 C), 129.57 (d, 3 C), 129.64 (d, 3 C), 131.13 (s, d, J = 52.0 Hz), 131.74 (s), 131.83 (d, d, J = 2.42 Hz, 3 C), 134.54 (s), 134.72 (d, 3 C), 134.81 (d, 3 C), 137.57 (s), 139.74 (s, 3 C), 155.38 (s, d, J = 3.86 Hz), 161.43 (s, d, J = 8.54 Hz) ppm; 31_{P NMR (242.92 MHz, CD} 2Cl2):

 = 45.22 ppm; HR MS (DART(+)) C33H26AuOP [M]+: calcd. 666.1381, found 666.1374.

6.3.1.3) (2-(4-Methoxyphenyl)benzofuran-3-yl) (triphenyl-5_{-phosphanyl) gold(I)}

According to GP D, Ph3PAuCl (146 mg, 294 µmol, 1.00 eq) and

AgOTs (82.1 mg, 294 µmol, 1.00 eq) were dissolved in 50.0 mL THF and stirred for one hour at room temperature. Triethylamine (297 µL, 208 mg, 2.08 mmol, 7.00 eq) and 2-((4-methoxyphenyl)-ethynyl)phenol 25OMe (67.3 mg, 300 µmol, 1.02 eq) were added and

the mixture was stirred for 18 hours. Recrystallization yielded the product 46OMe,Ph3P (155 mg, 277 µmol, 77%) as a colorless,

crystalline solid. TS-665 M.p.: decomp > 189 °C; IR (ATR): ṽ = 633, 643, 694, 709, 741, 779, 808, 832, 886, 925, 969, 998, 1009, 1026, 1046, 1070, 1101, 1172, 1242, 1284, 1302, 1331, 1414, 1434, 1448, 1464, 1490, 1538, 1581, 1609, 2837, 2939, 2991, 3048 cm-1_;1_{H NMR (600.13 MHz,} CD2Cl2):  = 3.83 (s, 3 H), 6.83-6.90 (m, 2 H), 7.12 (t, J = 7.21 Hz, 1 H), 7.13-7.18 (m, 1 H), 7.45 (d, J = 7.85 Hz, 1 H), 7.47-7.60 (m, 9 H), 7.63-7.71 (m, 6 H), 7.76 (d, J = 7.39 Hz, 1 H), 8.42-8.27 (m, 2 H) ppm; 13_{C NMR (150.92 MHz, CD} 2Cl2):  = 55.65 (q), 110.46 (d), 113.92 (d, 2 C), 121.75 (d), 123.23 (d), 124.75 (d), 127.12 (d, 2 C), 127.37 (s), 129.55 (d, 3 C), 129.63 (d, 3 C), 131.12 (s, d, J = 51.8 Hz), 131.81 (d, d, J = 2.33 Hz, 3 C), 134.70 (d, 3 C), 134.79 (d, 3 C), 139.81 (s, d, J = 2.51 Hz, 3 C), 139.98 (s, d, J= 118 Hz), 155.31 (s, d, J = 4.96 Hz), 159.61 (s), 162.25 (s, d, J = 10.32 Hz) ppm; 31_{P NMR (242.92 MHz, CD} 2Cl2):

 = 45.30 (s) ppm; HR MS (DART(+)) C33H27AuO2P [M+H]+: calcd. 683.1409, found