Optimization of the sulfonylactonization of lactam-tethered alkenoic acid 1a^a.

Entry	Deviation from conditions A	% Yield of 2a
1	EtOAc as solvent	61
2	THE as solvent	69
3	MTBE as solvent	53
4	Nitromethane as solvent	68
5	1,4-Dioxane as solvent	49
6	Dichloroethane as solvent	22
7	DMSO as solvent	48
8	PhMe	12
9	DMF	21
10	MeOH	0
11	CF3CH2OH	0
12	TMO	72
13	Cu(MeCN)4PF6 omitted	0
14	Cul in place of Cu(MeCN)4PF6	<5
15	CuBr in place of Cu(MeCN)4PF6	22
16	CuCI in place of Cu(MeCN)4PF6	48
17	CuOTf in place of Cu(MeCN)4PF6	<5
18	Cu(OAc)2 in place of Cu(MeCN)4PF6	0
19	Cu(NO3)2 3H2O in place of Cu(MeCN)4PF6	0
20	DMAP omitted	18
21	DBU in place of DMAP	73
22	KF in place of DMAP	51
23	Et3N in place of DMAP	38
24	2,2′-Bipyridine in place of DMAP	15
25	After 4 h at 60 °C	53
26	After 36 h at room temperature	75

^aRelative configuration established by NOESY noe’s between a and b as well as between b and c.