Divergent access to 5,6,7-perifused cycles

Abstract

Nitrogen-containing heterocycles are the key components in many pharmaceuticals and functional materials. In this study, we report a transition metal-catalyzed high-order reaction sequence for synthesizing a structurally unique N-center 5,6,7-perifused cycle (NCPC). The key characteristics include the formation of a seven-membered ring by the 8π electrocyclization of various alkenes and aromatic heterocycles as π-components, in which metal carbene species are generated that further induce the cleavage of the α-C-H or -C-C bond. Specifically, the latter can react with various nucleophilic reagents containing -O, -S, -N, and -C. The stereo-controlled late-stage modification of some complicated pharmaceuticals indicates the versatility of this protocol.

The lack of efficient and diverse synthesis strategy has hindered the study of perifused cycles. Here, the authors report a metal-catalyzed cascade electrocyclization to access 5,6,7-perifused cycles, and demonstrated the versatility of this protocol in the late-stage modification of pharmaceuticals.