Cycloaddition of carbon dioxide and epoxides using pentaerythritol and halides as dual catalyst system.

The combination of pentaerythritol with nucleophilic halide salts such as nBu4NI is used as a dual catalyst system for the cycloaddition of carbon dioxide (CO2) with a broad range of organic epoxides yielding the respective cyclic carbonates. Due to synergistic effects of the organocatalysts, excellent yields and selectivities could be achieved under mild reaction conditions. Moreover, the nontoxic, cost-efficient, and readily available system is easily recyclable without significant loss of reactivity, representing an exceptional sustainable approach for the fixation of CO2.