The regioselective annulation of alkylidenecyclopropanes by Rh(III)-catalyzed C–H/C–C activation to access spirocyclic benzosultams

Functionalized benzosultams are an essential class of structural motif found in various biologically active molecules. The synthesis of spirocyclic benzosultams from N-sulfonyl ketimine and alkylidenecyclopropanes (ACPs) under the catalysis of Rh(III) has been developed. This transformation enables the formation of two C–C bonds and a double bond with high E-selectivity through C–H and C–C bond activation. This reaction proceeded smoothly with excellent regioselectivity, high efficiency, and tolerance for various functional groups.