Table 2.

Substrate Scope^a

entry	substrate	product	yieldb
1			71%
2	1b, R = SES	2b, R = SES	55%
3	1c, R = Ns	2c, R = Ns	51%
4	1d, R = Ms	2d, R = Ms	50%
5			73%
6			22%
7			43%
8			83%
8	1h, Ar = 4-F-Ph	2h, Ar = 4-F-Ph	81%
9	1i, Ar = 4-MeO-Ph	2i, Ar = 4-MeO-Ph	85%
10			55%

^aReaction conditions used: 1a (0.174 mmol, 1 equiv), Cu(eh)₂ (0.026 mmol, 15 mol %), TEMPO (0.035 mmol, 20 mol %), toluene (1.74 mL) and O₂ (1 atm, balloon).

^bIsolated yield after column chromatography

^c22% of the (Z)-isomer of 1f was recovered.

SES = 2-(trimethylsilyl)ethanesulfonyl, Ns = 4-nitrophenylsulfonyl, Ms = methane sulfonyl.