Table 1. Reaction Optimization Conditions^a.

entry	deviation in conditions	yield (%)
1	standard conditions	79 (63%)
2	2 equiv Zn(0)	21
3	2 equiv Mn(0)	24
4	2 equiv TDAE	43
5	no reductant	<1
6	diethylzinc bromide	<1
7	phenethylzinc bromide	58
8	no additives	49
9	dioxanylzinc bromide	56
10	cyclopropylzinc bromide	59
11	tert-butylzinc bromide	46
12	1-ethylpropylzinc bromide	70
13	DMF instead of NMP	66
14	DMSO instead of NMP	70
15	toluene instead of NMP	25
16	THF instead of NMP	29
17	MeCN instead of NMP	0

^a0.1 mmol scale reactions in 0.5 mL of solvent.¹H NMR yields using pyrene as an internal standard. The value in parentheses is the isolated yield [diastereomeric ratio (dr) = 1:1] from 0.5 mmol. The dr was determined by ¹H NMR of the crude reaction mixture.