Copolymerization of carbon dioxide and cyclic monomers to form polycarbonates

Embodiments of the present disclosure describe initiating systems comprising an activator and an initiator, wherein the activator includes an alkyl borane or alkyl aluminum, wherein the initiator includes an organic cation and either an alkali metal or a compound containing an active protic hydrogen. Embodiments of the present disclosure further describe methods of making a polycarbonate comprising contacting a cyclic monomer and carbon dioxide in the presence of an activator and an initiator to form a polycarbonate, wherein the catalyst is one or more of an alkyl borane and alkyl aluminum, wherein the initiator includes an organic cation and either an alkali metal or a compound containing an active protic hydrogen.