Iridium-catalyzed regiospecific and stereospecific allylic amination for the syntheses of α,β-unsaturated γ-amino esters and the bifurcation of the reaction pathway leading to the formation of oxazolidin-2-ones

Abstract

A pair of iridium-catalyzed regiospecific and stereospecific reactions of the carbonates of γ-hydroxy α,β-unsaturated esters were developed. The reaction pathways are strongly affected by the choice of amines employed. A diverse range of γ-substituted α,β-unsaturated γ-amino esters were prepared in excellent yields with various amine nucleophiles such as benzylamine, diallylamine, morpholine, aniline and N-methylaniline. Substitution at the γ-position was well tolerated, encompassing alkyl, aryl and heteroaryl substituents. Enantioenriched (E)-α,β-unsaturated γ-amino esters could also be synthesized from the corresponding enantioenriched allylic carbonates with complete chirality transfer. In sharp contrast, a series of 3,4-disubstituted oxazolidin-2-ones were obtained by using allylamine as a nucleophile.