Table 3.

Preparation of cyclic systems utilizing 15.^[a]

Entry	NuLi	E+	Quench	Product	Yield
1	nBuLi		A	41	68%
2	nBuLi		A	42	69%
3	nBuLi		B	43	72%
4	44	BnBr	B	45	60%
5	44		B		64%
6	47		B		67%

^[a]Reaction conditions: i) 15, Et₂O, –78 ° C, then slow addition of NuLi; ii) BnBr, HMPA, Et₂O, –78 ° C to –30° C; iii) quench A with sat. aq. NH₄Cl or quench B with 48 % aq. HF, then NaHCO₃.