GaCl3-Catalyzed [3 + 2]-Cycloaddition/Esterification Cascade of Donor–Acceptor Cyclopropanes With Salicylaldehydes for the Synthesis of Tetrahydro-4 H-Furo[3,2-c]Chromen-4-Ones

Abstract

A GaCl₃-catalyzed [3 + 2]-cycloaddition/intramolecular esterification cascade of donor–acceptor cyclopropane-1,1-diesters with salicylaldehydes has been reported. A wide range of tetrahydro-4H-furo[3,2-c]chromen-4-ones have been efficiently delivered in moderate to good yields. Mechanistic studies suggest that the reaction involves the [3 + 2]-cycloaddition followed by intramolecular esterification to access 4H-furo[3,2-c]chromenones.