Chemical fixation of carbon dioxide catalyzed by binaphthyldiamino Zn, Cu, and Co salen-type complexes

Binaphthyldiamino salen-type Zn, Cu, and Co complexes can efficiently catalyze reactions of epoxides with carbon dioxide in the presence of various catalytic amounts of organic bases. The simplest binaphthyldiamino salen-type Zn complex gave the five-membered cyclic carbonate 2 in excellent yield in the presence of triethylamine. A Lewis acid and Lewis base cocatalyzed mechanism is proposed.