Table 1. Effect of Additives^a.

		yield (%)b
entry	additive	2a	3
1	LiBr	0	72 (67)c
2	−	78 (70)c	0
3	LiCl	0	13
4d	n-Bu4NBr	0	34
5e	n-Bu4NCl	0	50
6	n-Bu4NHSO4	0	13
7	NaBr	0	26
8	KBr	0	23
9	LiBF4	41	0

^aAll reactions were conducted with 0.194 mmol of 1 in DME (1.0 mL).

^bDetermined by ¹H NMR analysis using an internal standard.

^cIsolated yield is given in parentheses.

^dYnone 1 was recovered in 29% yield.

^eYnone 1 was recovered in 25% yield.