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.