Table 1 Effect of reaction parametersa

From: Site- and enantioselective cross-coupling of saturated N-heterocycles with carboxylic acids by cooperative Ni/photoredox catalysis

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Entry

Variation from standard conditions

Yield (%)b

r.r. (3a/3b)b

ee of 3a (%)c

ee of 3b (%)c

1

None

69

28:1

95

–

2

NiBr2·glyme, instead of NiCl2·glyme

19

1:1.7

92

73

3

NaHCO3, instead of 2,6-lutidine

58

24:1

85

–

4

i-PrOAcd, instead of benzene

71

20:1

89

–

5

1.5 equiv of NaBr added

39

2.8:1

95

74

6

1.0 equiv of H2O added

69

39:1

93

–

7

under air in a capped 4-mL vial

70

27:1

95

–

8

No Ni, Ir, or light

0

–

–

–

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  1. aStandard reaction conditions: C−H nucleophile 1 (0.3 mmol), carboxylic acid 2 (0.1 mmol), NiCl2·glyme (10 mol%), (S, R)-L1 (13 mol%), Ir photocatalyst (1 mol%), DMDC (1.5 equiv), 2,6-lutidine (1.5 equiv), benzene (0.1 M), 427 nm blue LEDs (40 W), 20 °C, 24 h.
  2. bThe combined yields of 3a and 3b, and the regioselective ratios were determined via GC analysis.
  3. cDetermined via HPLC analysis.
  4. dIsopropyl acetate.
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