Table 1 Optimization of the reaction conditionsa

From: Bicarbonate-binding catalysis for the enantioselective desymmetrization of keto sulfonium salts

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Catalyst

Solvent

T (°C)

Yield (%)b

e.r. (R:S)c

1

–

CH2Cl2

r.t.

n.r.

–

2

2a

CH2Cl2

r.t.

87

16:84

3

2b

CH2Cl2

r.t.

92

35:65

4

2c

CH2Cl2

r.t.

90

90:10

5

2d

CH2Cl2

r.t.

88

91.4:8.6

6

2e

CH2Cl2

r.t.

76

90.3:9.7

7

2f

CH2Cl2

r.t.

84

35.7:64.3

8d

2d

CH2Cl2

r.t.

86

87.5:12.5

9

2d

THF

r.t.

87

94.4:5.6

10

2d

Toluene

r.t.

79

94:6

11

2d

C6F6

r.t.

82

89:11

12

2d

CHCl3

r.t.

90

95:5

13

2d

CHCl3

40

96

70.6:29.4

14

2d

CHCl3

0

77

96:4

15

2d

CHCl3

−20

65

92.7:7.3

  1. aStandard reaction conditions: 0.05 mmol of 1a, 0.06 mmol of NaHCO3 and 0.01 mmol of 2 (20 mol%) in 0.25 mL of solvent.
  2. bIsolated yield.
  3. cEnantiomeric ratio was determined by supercritical fluid chromatography (SFC).
  4. d10 mol% of catalyst was used.
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