Table 1 Optimization studies.

From: Asymmetric C(sp3)–H functionalization of unactivated alkylarenes such as toluene enabled by chiral Brønsted base catalysts

View full size image

Entry

Base-Cat.

Ligand

Yield (%)

ee (%)

1

KOtBu-LiTMP

None

Trace

–

2

KOtBu-LiTMP

L1

Trace

–

3

KOtBu-LiTMP

L1a

92

36

4

KCH2SiMe3

L1

86

56

5

KCH2SiMe3

L2

82

40b

6

KCH2SiMe3

L3

95

30b

7

KCH2SiMe3

L4

61

6b

8

KCH2SiMe3

L5

90

31

9

KCH2SiMe3

L6

96

75

  1. Reaction conditions (unless otherwise noted): 1a (0.50 mmol), 2a (1.0 mL), base catalyst (0.050 mmol), ligand (0.055 mmol), –78 °C, 18 h.
  2. aL1 (22 mol%, 0.11 mmol) was used.
  3. b(R)-3aa was obtained as a major enantiomer.
Back to article page