Chiral Ferrocenyl P,N-Ligands for Palladium-Catalyzed Asymmetric Formal [3 + 2] Cycloaddition of Propargylic Esters with β-Ketoesters: Access to Functionalized Chiral 2,3-Dihydrofurans.

A highly enantioselective palladium-catalyzed [3 + 2] cycloaddition of propargylic esters with β-ketoesters has been realized by employing a newly developed chiral ferrocene/benzimidazole-based P,N-ligand. This protocol features a good tolerance of functional groups in both propargylic esters and β-ketoesters, thereby delivering a variety of highly functionalized chiral 2,3-dihydrofurans bearing an exocyclic double bond at the 3-position in good yields and with high enantioselectivities (up to 98% ee).