Stereoselective formation of α-fluoro-α-trifluoromethyl-γ-lactones starting from γ-hydroxy-α,β-unsaturated sulfones and a hexafluoropropene-diethylamine adduct (PPDA)

Abstract

( E)-3-Hydroxy-1-alkenyl p-tolyl sulfones ( 1) reacted with a hexafluoropropene-diethylamine adduct (PPDA) to afford α-fluoro-α-(trifluoromethyl)-β-[( p-tolylsulfonyl)methyl]-γ-lactones ( 2). This reaction is so stereoselective that only one diastereomer of 2 is detected in the reaction mixture. A plausible mechanism for this intriguing reaction is discussed.