LiCl-Mediated and Palladium-Catalyzed Oxidative Cyclization of Furan-Ynes via Dearomatizing Alkoxyalkenylation of Furan.

A LiCl-mediated and palladium(II)-catalyzed oxidative cyclization of furan-ynes via dearomatizing alkoxyalkenylation of furan is reported to afford polyfunctionalized spiro-dihydrofurans with diastereospecification and high Z / E selectivity. This protocol is likely to involve chloropalladation of alkynes, subsequent intramolecular dearomatizing alkenylation of furan, and final O -allylation. The density functional theory (DFT) calculations demonstrated that the coordination of furan with dissolved Li + weakens its nucleophilicity and promoted the Heck insertion, and dissolved Cl - promoted chloropalladation of alkynes.