Table 1 Optimization of reaction conditionsa.

From: Dichotomy of platinum(II) and gold(III) carbene intermediates switching from N- to O-selectivity

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Entry

Catalyst

Solvent

Yield (%)b

3a

4a

5a

1

5 mol% Me4tBuXPhosAuCl/AgNTf2

1, 2-DCE

20%

<5%

45%

2

5 mol% Me4tBuXPhosAuCl/AgSbF6

1, 2-DCE

10%

13%

30%

3

5 mol% L1AuCl/AgSbF6

1, 2-DCE

8%

<5%

40%

4c

5 mol% tBuXPhosAuCl/AgSbF6

1, 2-DCE

12%

36%

18%

4

10 mol% AuCl3

1, 2-DCE

38%

36%

13%

5

10 mol% PicAuCl2

1, 2-DCE

<5%

61%

10%

6

10 mol% AuppyCl2

1, 2-DCE

<5%

<5%

0%

7d

10 mol% PyrAuCl3

1, 2-DCE

43%

32%

<5%

8d

10 mol% Pyr-1AuCl3

1, 2-DCE

59%

30%

<5%

9d, f

10 mol% Pyr-2AuCl3

1, 2-DCE

70%

19%

<5%

10d

10 mol% Pyr-3AuCl3

1, 2-DCE

67%

20%

<5%

11

10 mol% PtCl2

1, 2-DCE

0%

8%

0%

12

10 mol% PtCl2 (1 atm. CO)

Toluene

0%

37%

<5%

13e

10 mol% PtCl2/P(C6F5)3

Toluene

0%

21%

0%

14e

10 mol% PtCl2/L1

Toluene

0%

62%

<5%

15e

10 mol% PtCl2/L2

Toluene

0%

84%

0%

16e, f

10 mol% PtCl2/L3

Toluene

0%

90%

0%

17e

10 mol% Pt(PPh3)4

Toluene

0%

0%

0%

  1. Ad 1-adamantyl, 1, 2-DCE 1, 2-dichloroethane, NTf2 bis(trifluoromethanesulfonyl)imide.
  2. a1a (0.2 mmol, 2 equiv.) and 2a (0.1 mmol) in 2 ml solvent at 70 °C.
  3. bIsolated yield.
  4. cAt 25 °C.
  5. d1a (0.4 mmol, 4 equiv.), 4 ml 1, 2-DCE.
  6. eIn 1 ml toluene.
  7. fThe best condition.
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