Rhodium-catalyzed atroposelective access to trisubstituted olefins via C–H bond olefination of diverse arenes†

Abstract

The atroposelective synthesis of axially chiral acyclic olefins remains a daunting challenge due to their relatively lower racemization barriers, especially for trisubstituted ones. In this work, atroposelective C–H olefination has been realized for synthesis of open-chain trisubstituted olefins via C–H activation of two classes of (hetero)arenes in the coupling with sterically hindered alkynes. The employment of phenyl N-methoxycarbamates as arene reagents afforded phenol-tethered olefins, with the carbamate being a traceless directing group. The olefination of N-methoxy-2-indolylcarboxamides afforded the corresponding chiral olefin by circumventing the redox-neutral [4 + 2] annulation. The reactions proceeded with excellent Z/ E selectivity, chemoselectivity, regioselectivity, and enantioselectivity in both hydroarylation systems.

Abstract

C–H olefination of alkynes has been realized as an efficient approach to access axially chiral trisubstituted olefins, where two classes of arenes have been identified.