Superbase/saccharide: An ecologically benign catalyst for efficient fixation of CO2 into cyclic carbonates

An ecologically benign catalytic system consisting of superbase and saccharide was developed for CO₂ chemical fixation with epoxides under metal-free and halide-free conditions. Because of the synergistic effect played by superbase and saccharide on the activations of CO₂ and epoxide, the reaction could be performed with good activity and selectivity. A possible catalytic mechanism of the hydrogen-bonding of saccharide and activation of the carbon atom by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was proposed. The process is a simple, biocompatible, and ecological route for CO₂ chemical fixation into high-value chemicals.