Rh(III)-Catalyzed Oxidative C–H Activation/Annulation of Salicylaldehydes with Masked Enynes for the Synthesis of Chromones

Abstract

A rhodium(III)-catalyzed oxidative C–H activation/annulation of salicylaldehydes with propargylic acetates has been developed for the regioselective synthesis of 3-vinyl chromones in good yields with broad functional group tolerance. 3-Vinyl chromones were converted into biologically active benzo[c]xanthone by I2-mediated oxidative electrocyclization.

Theoretical Investigations on the Rh(III)-Catalyzed Oxidative C–H Activation/Annulation of Salicylaldehydes with Masked Enynes: Mechanism Insights and Regioselectivity Origins

“…Recently, Huang and Yao 12 reported the Cp*Rh(III)catalyzed reaction of salicylaldehydes with propargylic acetates, wherein the enynes are inserted into the in situ generated…”

“…Recently, Huang and Yao 12 reported the Cp*Rh(III)-catalyzed reaction of salicylaldehydes with propargylic acetates, wherein the enynes are inserted into the in situ generated 3-vinyl chromones ( Scheme 1 ). The corresponding possible reaction mechanisms postulated by Huang, Yao, and co-workers are demonstrated in Scheme 2 .…”