Direct organocatalytic Wittig/Hetero-Diels-Alder reactions in one-pot: synthesis of highly-substituted tetrahydropyranones

Abstract

A practical and environmentally friendly organocatalytic one-pot strategy designed to furnish the hetero-Diels-Alder products was shown to be effective in the preparation of disubstituted tetrahydropyranones in a highly selective manner. (S)-1-(2-pyrrolidinylmethyl)pyrrolidine catalyzed an asymmetric assembly reaction involving a hetero-Diels-Alder reaction between alkylidene-and arylidene-acetones generated in situ from Wittig reactions with diethyl ketomalonate to furnish the substituted tetrahydropyranones in moderate to very good yields with moderate enantioselectivity.