Synthesis of dihydrobenzofurans from phenolic mannich bases and their quaternized derivatives

Abstract

Reaction of dimethylsulphoxonium methylide with quaternized derivatives of phenolic Mannich bases, and in certain cases with the bases themselves, constitutes a useful synthesis of dihydrobenzofurans. On the other hand treatment of those same quaternized derivatives with diazomethane may be a useful alternative procedure for the preparation of coumarans with base-sensitive groups.