Furan-2-Carboxamides as Dienes in Cascade SN2’/Intramolecular Diels-Alder Reaction with MBH Carbonates

Abstract

Herein we describe a Lewis base-initiated cascade SN2’/Diels–Alder reaction of Morita–Baylis–Hillman carbonates with electron-deficient furan-2-carboxamides. This transformation enables efficient construction of densely functionalized polycyclic lactams in up to 99% yield with > 20:1 diastereoselectivity. The furan-2-carboxamides exhibit broad substrate scope, encompassing various N-aryl, N-heteroaryl, and other amide analogues. Control experiments revealed that the Diels-Alder step proceeds via a thermal pathway, and that the steric strain of the amide tether is essential for the cycloaddition. This strategy allows electron-deficient furan-2-carboxyamides to serve as competent dienes, thereby expanding the toolbox for constructing complex heterocycles.