The Construction of Furocoumarins through Iron-Catalyzed Relay Annulation of Oxime Esters with 4-Hydroxycoumarins.

An iron-catalyzed relay annulation protocol was disclosed, which utilizes oxime esters and 4-hydroxycoumarins as the readily available starting materials and showcases broad substrate scope and good functional group tolerance. This method allows the simultaneous generation of two C-C and one C-O bonds and two rings in one step, affording structurally new furocoumarins in moderate to good yields.