Iron promoted allylic amination of unactivated alkenes

Abstract

Nitrogen-containing compounds are important because of their biological activities in natural and synthetic products. Thus, the direct allylic amination of olefins via C-N bond formation is an area of significant interest in organic chemistry. In this study, iron(II), copper(II) and manganese(II) complexes of tris(2-pyridylmethyl)amine (TPA, 62), N,N’-bis(2-pyridylmethyl)-N,N’-dimethylethane-1,2-diamine (BPMEN, 63), lithium (S)-1-((6-(hydroxymethyl)pyridine-2-yl)methyl)pyrrolidine-2-carboxylate (56), lithium (2S,2S’)1,1̍-(pyridine-2,6-diylbis(methylene))dipyrrolidine-2-carboxylate (57) and iron(II) complexes of the tetramethyl cyclam (TMCy, 58), tris(2-dimethylaminoethyl)amine (Me6-TREN, 59), N,N’-bis(2’-(dimethylamino)ethyl)-N,N’-dimethylpropane-1,3-diamine (Me4-dimethyl tetramine, 60) and cross-bridged cyclam ligand (DMCBCy, 61) have been investigated as catalysts for the allylic amination of cyclohexene. Several of these complexes have proven effective catalysts for the allylic hydroxyamination reaction. Among them FeTPA was found to be optimal, producing moderate to good yields using N-Cbz-hydroxylamine (CbzNHOH) in acetonitrile at room temperature. The generality of this reaction has been studied using a series of hydroxylamines and alkene substrates.