Copper-Catalyzed SN2'-Type Allylic Substitution of gem-Dichlorocyclobutenones with Cyclopropanols.

Both gem-dichlorocyclobutenones and cyclopropanols are versatile building blocks in organic synthesis. Herein, we report a Cu/dppp-catalyzed SN2'-type allylic substitution of gem-dichlorocyclobutenones with cyclopropanols. The reaction proceeds smoothly via a copper homoenolate intermediate under mild conditions and exhibits a broad substrate scope, affording densely functionalized cyclobutenones with high efficiency. Moreover, a scale-up experiment and several product derivatizations were conducted to showcase the synthetic utility of this method.