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 CO ₂. Doubleteam: The combination of pentaerytrithol with tetrabutylammonium iodide leads to an efficient catalytic system for the cycloaddition of carbon dioxide (CO₂) with various epoxides to cyclic carbonates. The nontoxic, metalfree, and cost-efficient dual catalysts, as well as the easy recyclability result in an exceptional sustainable organocatalytic approach for the fixation of carbon dioxide.