Table 1 Effect of reaction parametersa.

From: Rhodium-catalyzed intermolecular enantioselective Alder–ene type reaction of cyclopentenes with silylacetylenes

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Entry

Deviation of standard conditions

Yield of 3a (%)b

ee (%)c

1

None

96

95

2

L1-3 instead of L6

trace

–

3

L4 instead of L6

44

76

4

L5 instead of L6

77

84

5

Rh(COD)2OTf instead of [Rh(COD)OMe]2

82

92

6

[Rh(COD)Cl]2 instead of [Rh(COD)OMe]2

90

90

7

[Cp*RhCl2]2 instead of [Rh(COD)OMe]2

trace

–

8

Pd(dba)2 instead of [Rh(COD)OMe]2

trace

–

9

AcOH instead of PhMe2CCO2H

55

69

10

PhCO2H instead of PhMe2CCO2H

95

68

11

TsOH instead of PhMe2CCO2H

n.d.

–

12

AgSbF6 instead of NaBARF

87

92

13

AgPF6 instead of NaBARF

40

60

14

CHCl3 instead of DCM

84

88

15

toluene instead of DCM

85

91

16

THF instead of DCM

n.d.

–

  1. aStandard conditions: 1a (0.10 mmol), 2a (0.30 mmol), [Rh(COD)OMe]2 (2.5 mol%), L6 (6.0 mol%), NaBARF (10 mol%), PhMe2CCO2H (60 mol%) in 1.0 mL DCM, 80 °C, 36 h, under argon. TIPS = SiiPr3.
  2. bIsolated yield, d.r. > 20:1, E/Z > 20:1, determined by 1H NMR analysis.
  3. cDetermined by HPLC analysis on a chiral stationary phase.
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