Entry

Catalyst

Solvent

Temp (^oC)

Yield (%)^b

1

5a

CH₂Cl₂

rt

74

2

5b

CH₂Cl₂

rt

63

3

4a

CH₂Cl₂

rt

67

4

4b

CH₂Cl₂

rt

61

5

5a

Toluene

rt

34

6

5a

CHCl₃

rt

81

7

5a

ClCH₂CH₂Cl

rt

54

8

5a

CHCl₃

0

69

9

5a

CHCl₃

40

91