Synthesis of Furo3,2‐ccoumarins via Lewis Acid‐Mediated Multicomponent Tandem Reactions

An efficient method for the synthesis of furo3,2‐ccoumarins through FeCl 3 or ZnCl 2 ‐mediated multicomponent tandem reactions in the presence of arylglyoxal monohydrates, 4‐hydroxycoumarin, and allyltrimethylsilane in toluene is reported. This reaction involves the formation of two C‐C bonds and one C‐O bond. This process provided the privileged structures of furo3,2‐ccoumarins in moderate to good yields under mild conditions. Notable features of the procedure such as easily accessible starting materials, good functional group tolerance, and high atom economy have been developed.