Nitrene‐Mediated Enantioselective Intramolecular Olefin Oxyamination to Access Chiral γ‐Aminomethyl‐γ‐Lactones

Abstract

Attaching a nitrene precursor to an intramolecular nucleophile allows for a catalytic asymmetric intramolecular oxyamination of alkenes in which the nucleophile adds in an endocyclic position and the amine in an exocyclic fashion. Using chiral‐at‐ruthenium catalysts, chiral γ‐aminomethyl‐γ‐lactones containing a quaternary carbon in γ‐position are provided in high yields (up to 99 %) and with excellent enantioselectivities (up to 99 % ee). DFT calculations support the possibility of both a singlet (concerted oxyamination of the alkene) and triplet pathway (stepwise oxyamination) for the formation of the predominant stereoisomer. γ‐Aminomethyl‐γ‐lactones are versatile chiral building blocks and can be converted to other heterocycles such as δ‐lactams, 2‐oxazolidinones, and tetrahydrofurans.