InCl3-catalyzed regio- and stereoselective thiolysis of alpha,beta-epoxycarboxylic acids in water.

[reaction: see text] The thiolysis of alpha,beta-epoxycarboxylic acids 1a-e by thiols 2a,b is more efficient in water than in dichloromethane or SFC. At pH 9.0 phenylthiolate generally attacks the C-alpha carbon while at pH 4.0, and in the presence of InCl3 (10 mol %), the thiolysis is exclusively C-beta regioselective. In all cases, the processes are completely anti-diasteroselective, and the corresponding products 3, 4, and 5 have been isolated in good yields. Both water and catalysts have been recovered and reused.