Metal‐Free Cycloaddition of Epoxides and Carbon Dioxide Catalyzed by Triazole‐Bridged Bisphenol

Abstract

Abstract1,2,3‐triazole‐bridged bisphenol has been developed as organocatalyst in the coupling of CO2 and epoxides. In the absence of halide co‐catalyst, halomethyl‐substituted epoxides reacted with 1 bar CO2, while a series of aryl‐substituted epoxides were transformed into cyclic carbonates in 57–95 % yields at 120 °C and 10 bar pressure. 1,2,3‐triazole‐bridged bisphenol is thus among the most efficient organocatalysts that are active in the absence of both metal and halide. For alkyl‐substituted epoxides, good yields of 80–95 % were obtained under 1 bar CO2 in the presence of halide. The bisphenol was recycled 14 times in the presence of halide, and 5 times in the absence of halide. The two hydroxyl groups of bisphenol are proposed to work synergistically in the catalytic cycle.