Table 2 Reaction optimization of monocyclic benzyl alcohol involved benzylation reactiona.

From: Catalytic asymmetric Tsuji–Trost α−benzylation reaction of N-unprotected amino acids and benzyl alcohol derivatives

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Entry

Ar*CHO

R

Ligand

Time (h)

yield (%)b

ee (%)c

1

3f

Et

dppp

12

26

75

2d

3f

Et

(R)-L1

9

60

78

3d

3a

Et

(S)-L1

12

51

19

4d

3a

Et

(R)-L1

12

60

72

5

3f

tBu

(R)-L1

9.5

83

95

6d

3f

tBu

dppp

9.5

50

83

7

rac-3a

tBu

(R)-L1

9.5

62

74

  1. aReaction conditions: 1 (0.30 mmol), 2a (0.20 mmol), 3 (0.02 mmol), L1 (0.02 mmol), [Pd(C3H5)Cl]2 (0.01 mmol), TDMAIP (0.28 mmol), and ZnCl2 (0.08 mmol) were stirred in mesitylene (0.5 mL) at 60 °C for indicated time.
  2. bIsolated yield.
  3. cThe enantioselective excess was determined by chiral HPLC.
  4. dWith 10 mol% palladium and 20 mol% (R)-L1.
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