Reductive [3 + 2] Annulation of Quinolines and Epoxides for Access to Fused 1,3-Oxazolidines by a Co-Catalyst System

Employing the synergistic Ir-SAs@B-ZrO₂/SiO₂ and (C₆F₅)₃B catalytic system with PhSiMe₂H as the reductant, we herein report a new reductive annulation reaction between quinolines and epoxides. This transformation exhibits broad substrate and functional group compatibility, good iridium catalyst reusability, and high step economy. It provides a practical route for directly constructing N-heterocycle-fused 1,3-oxazolidines from readily available starting materials, surpassing conventional methods in both efficiency and sustainability. The present strategy, which merges partial hydro-dearomatization with in situ intermediate transformation, is anticipated to inspire further development of valuable synthetic transformations.