Lewis acid mediated elimination and rearrangement reactions of alpha-chlorosulfides derived from phenylthio-substituted 4,5-dihydrofuran-3(2H)-ones.

Phenylthio-substituted 4,5-dihydrofuran-3(2H)-ones were converted into alph a-chlorosulfides in a highly diastereoselective manner with sulfuryl chlori de. Treatment of the chlorides with stoichiometric amounts of Lewis acids g ave furan-3(2H)-one products resulting from elimination and aryl group migr ations. Similar behaviour was observed with an alpha-acetoxy sulfide deriva tive. The X-ray crystal structures of a representative alpha-chlorosulfide and of a novel, ring sulfenylated product were determined.