An iron-catalysed radical cyclization/C(sp3)–H alkylation cascade between γ,δ-unsaturated oxime esters and glycine derivatives: access to pyrroline-containing amino acids

Abstract

An iron-catalysed selective C_(sp³)–H alkylation method for glycine derivatives is reported. Using γ,δ-unsaturated oxime esters as both the alkylation reagent and terminal oxidant, N-aryl glycinates could be converted into a series of pyrroline-containing amino esters with a readily available iron catalyst and a phenanthroline-based ligand. Control experiments showed that the ligand plays a key role in tuning the chemoselectivity, while a radical–polar crossover pathway is proposed according to the mechanistic studies. Additionally, the products obtained with this method could be transformed into various valuable building blocks, including amino acids, amino alcohols and γ-lactams.