Table 1 Optimization of the reaction conditions

From: Copper-catalyzed asymmetric C(sp3)-H cyanoalkylation of glycine derivatives and peptides

View full size image

Entryd

Change from the “standard conditions”

Yield (%)b

Ee (%)c

1

None

80 (75)

93

2

Without Cu(MeCN)4PF6

0

--

3

Without DABCO

Trace

--

4

Without L2

28

0

5

With white LED

80

93

6

Under air

36

91

  1. aCondition: 1b (0.05 mmol), 2a (1.5 equiv), Cu(MeCN)4PF6 (10 mol%), L2 (11 mol%), DABCO (2.0 equiv), acetone (1.0 mL), room temperature, 12 h, and under argon atmosphere.
  2. bYield was determined by 1H NMR using 4-bromobenzaldehyde as an internal standard and isolated yield in parentheses.
  3. cEe (enantiomeric excess) was determined by HPLC on a Chiralpak IA-H column.
  4. dStandard conditions: 1b (0.1 mmol), 2a (2.0 equiv), Cu(MeCN)4PF6 (10 mol%), L2 (15 mol%), DABCO (2.0 equiv), acetone (0.5 mL), 0 °C, 18 h, and at argon atmosphere.
Back to article page