No activation barrier synthetic route of glycine from simple molecules (NH 3, CH 2, and CO 2) via carboxylation of ammonium ylide: a theoretical study by the scaled hypersphere search method

Abstract

A new synthetic route of glycine with no activation barriers, NH 3 + CH 2 + CO 2 → H 2NCH 2COOH, has been discovered by the scaled hypersurface search method for ab initio potential energy surfaces. The route is composed of two steps with no activation barriers, an addition reaction of ammonia with singlet methylene yielding ammonium ylide (NH 3 + 1:CH 2 → H 2CNH 3) followed by carboxylation of the ylide with carbon dioxide (H 2CNH 3 + CO 2 → H 2NCH 2COOH). A sideway reaction of the ylide decomposing into methyleneimine and hydrogen (H 2CNH 3 → H 2CNH + H 2) via new transition state was found in addition to an isomerization route to methylamine (H 2CNH 3 → CH 3NH 2).