Stereocontrolled construction of 3H-furo[3,4-b]chromen-1(9H)-one scaffolds via organocatalyzed Michael addition and the following intramolecular dehydration

摘要

An efficient approach for the stereocontrolled construction of 3H-furo[3,4-b]chromen-1(9H)-one skeleton has been successfully developed through a sequential Michael addition/intramolecular dehydration strategy. The Michael addition of tetronic acid to 2-((E)-2-nitrovinyl)phenols catalyzed by a bifunctional squaramide derived from L-tert-leucine, and the subsequent intramolecular dehydration promoted by concentrated sulfuric acid, proceed smoothly to give the corresponding pharmaceutically valuable 3H-furo[3,4-b]chromen-1(9H)-ones in acceptable yields with 79-97% ee.