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 C−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.