Construction of Cyclopropa[c]coumarins via cascade Michael-alkylation process of 3-cyanocoumarin with 2-bromomalonate

Abstract A convenient and efficient method for the synthesis of highly functionalized cyclopropa[c]coumarin derivatives in good to excellent yields via cascade Michael-alkylation process of 3-substituted coumarins and 2-bromomalonate was developed. Preliminary results indicated that using a chiral PTC strategy, the desired cyclopropanation product could be obtained in up to 41% ee.