Dual silane-promoted palladium catalysis: synthesis of phenols from carbon dioxide and 1,4-enynes

Abstract

A palladium-catalyzed reductive carbonylative benzannulation of 1,4-enynes with carbon dioxide (CO₂) as carbonyl source has been developed for the first time, offering an efficient approach to a wide range of multi-substituted phenols in high yields. The success of this transformation hinges on a synergistic dual silane reduction system: one silane acts as a reductant for the conversion of CO₂ to CO, while the other serves as a hydrogen source to generate Pd–H species. This method is operationally simple, exhibits broad substrate scope, and can be applied to the late-stage modification of complex pharmaceutical molecules as well as the synthesis of bioactive compounds such as thymol.