Table 1. Optimization Table^a.

entry	variations from standard conditionsa	yield (%)b of 3aa
1	none	97 (96)c
2	without PPh3	NR
3	BINAP instead of PPh3	NR
4	toluene instead of CHCl3	60
5	DCM instead of CHCl3	78
6	EtOAc instead of CHCl3	64
7	CDCl3 instead of CHCl3	93
8	1 equiv of 1a	46
9	2 equiv of 1a	82
10	0.2 mmol 1a and 2 equiv of 2a	20

^aUnless otherwise noted, the standard reaction conditions were as follows: 1a (0.6 mmol), 2a (0.2 mmol), solvent (0.5 mL).

^bThe yield was determined by ¹H NMR analysis of the crude reaction mixture using 1,3,5-trimethoxybenzene as an internal standard.

^cIsolated yield.