FeCl 3 -Catalyzed Cascade Reaction: An Efficient Approach to Functionalized Coumarin Derivatives.

An efficient and environmentally benign synthesis of 3-substituted or 3,4-disubstituted coumarins was accomplished via iron(III) chloride–catalyzed cascade reactions of salicylaldehydes and activated methylene compounds. The reaction preceded cleanly under mild reaction conditions to provide the desired coumarin derivatives in good to excellent yields. [ABSTRACT FROM PUBLISHER]