Regioselective Access to Structurally Diverse Coumarin Analogues through Iron‐Catalysed Annulation Reactions

A highly efficient iron-catalysed propargylation/alkyne oxacyclization/isomerization strategy is described. Biologically active furo[3,2-c]coumarins and pyrano[3,2-c]coumarins are expeditiously assembled in moderate to good yields and with a broad substrate scope. The regioselective access to different coumarins is mainly dependent on the terminal group of the secondary propargylic alcohol.