Highly Diastereoselective Synthesis of Multifunctionalized Dihydrofurans by a K₃PO₄-Promoted Michael Addition-Alkylation Reaction

A simple and beneficial strategy for the construction of 2,3-dihydrofurans from alpha-bromochalcones and alpha-substituted cyanoketones via Michael addition-alkylation reaction has been realized. This transformation was well compatible with various alpha-bromochalcones and alpha-substituted cyanoketones, and the corresponding multifunctionalized 2,3-dihydrofurans were obtained in up to 98 % yield. A highly diastereoselective variant of the reaction was also developed. Moreover, the reaction could be performed on gram-scale.