Table 1 Optimization of the reaction conditionsa

From: Stereodivergent synthesis of vicinal quaternary-quaternary stereocenters and bioactive hyperolactones

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Entry

1

Metal source/L

Yield (%)b

drc

eed

1

1a

Cu(OTf)2/BOX

trace

–

–

2

1a

Ni(OTf)2/BOX

trace

–

–

3

1a

Yb(OTf)3/L-PiMe 2

47

3:1

33

4

1a

Ni(OTf)2/L-PiMe 2

85

5:1

98

5

1a

Ni(OTf)2/L-PiMe 3

85

5:1

98

6

1a

Ni(OTf)2/L-RaMe 2

90

2:1

94

7

1b

Ni(OTf)2/L-PiMe 2

90

8:1

98

8

1c

Ni(OTf)2/L-PiMe 2

90

5:1

98

9

1b

Ni(BF4)2·6H2O/L-PiMe 2

96

8:1

98

10e

1b

Ni(BF4)2·6H2O/L-PiMe 2

96

10:1

99

11e

1d

Ni(BF4)2·6H2O/L-PiMe 2

94

5:1

99

12e

1e

Ni(BF4)2·6H2O/L-PiMe 2

90

1.5:1

99

  1. aUnless otherwise noted, the reactions were performed with 1 (0.1 mmol), and metal source/Ligand (1:1, 10 mol%), in DCE (1.0 mL) at 70 °C for 4 h
  2. bIsolated yield
  3. cThe dr value was determined by 1H NMR and HPLC analysis
  4. dDetermined by HPLC analysis on chiral stationary phases
  5. eAt 35 °C for 4 days
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