Table 1 Optimization of the formation of indole 3aa.

From: Reactant-induced photoactivation of in situ generated organogold intermediates leading to alkynylated indoles via Csp2-Csp cross-coupling

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Entry

1a:2a Ratio

Base

Additivesc

3aa, yield (%)a

4a, yield (%)a

1b

1:1.5

K2CO3

–

8

10

2c

1:1.5

K2CO3

1 mol% [Ir]

38

18

3

1:1.5

K2CO3

10 mol% PhCOPh

61

16

4

1:1.5

K2CO3

–

64

16

5

1:1.1

K2CO3

–

62

10

6

1:1.1

Na2CO3

–

4

10

7

1:1.1

Cs2CO3

–

10

6

8

1:1.1

CaCO3

–

0

0

9

1:1.1

K2CO3

1 equiv 18-C-6

14

16

  1. aNMR yield using 1,3,5-trimethoxybenzene as internal standard; all reactions run on a 0.1 mmol except for entries 3 and 4 (0.3 mmol).
  2. b5 mol% PPh3AuCl was used instead of 5 mol% [AuCF3].
  3. c[Ir] = [Ir[dF(CF3)ppy]2(dtbbpy)PF6].
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