Cyclization of γ,δ-Epoxy-α-cyanosulphones. A Simple, Diastereoselective Route to Cyclopropane Carboxylic Acids.
cyclisation of α-cyano-α-sulphonyl-γ,δ-epoxy carbanions proceeds with high yields and complete diastereoselectivity, to yield cyclopropanolactones, useful intermediates in the synthesis of cis-substituted cyclopropane carboxylic acids.