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).