InCl3-catalyzed regio- and stereloselective thiolysis of α,β-epoxycarboxylic acids in water

The thiolysis of alpha,beta-epoxycarboxylic acids la-e by thiois 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.