Synthesis of a chiral azodicarboxamide containing a bridging binaphthyl moiety: electrophilic amination reactions of achiral ester enolates

Abstract

A chiral azodicarboxamide 11 containing a bridging binaphthyl group has been prepared by an intermolecular cyclization reaction between the bis(N-methylamine) of 2,2′-dimethyl-1,1′-binaphthyl 6 and N,N′-bis(azidocarbonyl)hydrazine 9, followed by oxidation of the resulting hydrazodicarboxamide 10 with N-bromosuccinimide and pyridine. The crystal structure of azodicarboxamide 11 has been determined. Reaction of 11 with achiral oxazolidinone anions at –78 °C gives α-hydrazino acid derivatives with high stereoselectivity. The stereochemical outcome of the amination was determined by X-ray crystallography.