Molecular Iodine‐Catalyzed Sulfonyl‐Activated sp³ C−N Bond Cleavage for the C3‐Alkylation of 4‐Hydroxycoumarins

Abstract

A molecular iodine-catalyzed system for the coupling reaction of 4-hydroxycoumarins with N-benzylic sulfonamides via sp 3 CÀ N bond cleavage has been established. This procedure provides a series of C3-alkylated 4-hydroxycoumarins containing structurally diverse functional groups in good to excellent yields. Furthermore, the practicability of this method could be manifested efficiently in a gram-scale synthesis of drug coumatetralyl and access to a bioactive agent pyranocoumarin from obtained product.