Optimization of reaction conditions^a.

Entry	Base	Yieldb (3a, %)
1	LiHMDS	84 (75)c
2	nBuLi	48
3	tBuOLi	33
4	iPrMgCl	35
5	CH3MgBr	21

^aReactions conditions: 1 (0.1 mmol), 2a (0.12 mmol), base (0.105 mmol) in cyclohexane (2 mL), rt, 0.5 h.

^bDetermined by GC.

^cIsolated yield.