Nucleophilic epoxidation of alpha'-hydroxy dienyl sulfoxides.
A novel route to enantiopure densely functionalized epoxy sulfinyl tetrahydrofurans, based on the unexpected and highly stereoselective remote nucleophilic epoxidation of hydroxy 1-sulfinyl butadienes with t-BuOOK, followed by ring closure and subsequent epoxidation of the resulting sulfinyl dihydrofurans, is described. Alternatively, the treatment of these dienes with m-CPBA followed by acid-catalyzed cyclization gives rise to related sulfonyl dihydrofurans in high yields but with low selectivity. The stereochemical outcome of the nucleophilic epoxidation of these substrates has also been studied.