Table 1. Reaction optimization.^a.

Entry	Solvent	HCl source	Conc.	Conv./%a
1	DCE	HCl•DMPU	1.0	64
2	CH3CN	HCl•DMPU	1.0	22
3	CH3NO3	HCl•DMPU	1.0	30
4	EtOAc	HCl•DMPU	1.0	90
5	DMSO	HCl•DMPU	1.0	18
6	EtOAc	HCl•DMPU	0.5	89
7	EtOAc	HCl•DMPU	0.2	99
8	EtOAc	HCl, Et2O	0.2	32 (98)b
9	EtOAc	HCl, 2-propanol	0.2	99c
10	EtOAc	HCl, dioxane	0.2	65 (94)b
11	EtOAc	HCl, AcOH	0.2	99c
12	EtOAc	HCl, H2O	0.2	29 (65)b
13	EtOAc	CH3COCl/EtOH	0.2	99
14	EtOAc	TMSCl/MeOH	0.2	95

^aDetermined by GC-MS with dodecane as the internal standard.

^b24 h

^ccombined with thiolated side product.