SmI2-Catalyzed Coupling of Alkyl Housane Ketones and Alkenes in an Approach to Norbornanes.

Cross-coupling strategies involving strain-release have gained significant recent attention for the construction of complex molecular frameworks, particularly in the context of preparing bioisosteres for medicinal chemistry. While the reactivity of cyclopropanes and bicyclo[1.1.0]butanes (BCBs) has been extensively studied, higher homologues are emerging as valuable substrates for synthesis. For example, methods for the fragmentation and coupling of bicyclo[2.1.0]pentane, or housane, ketones show promise, but are currently limited in substrate scope. Here, we describe a mild, atom-economical, samarium diiodide (SmI2) catalyzed fragmentation and coupling of alkyl and aryl housane ketones with alkenes that grants access to functionalized norbornane structural motifs, not easily accessible by classical cycloaddition approaches, and with considerable potential for further manipulation.