Desymmetrization of Prochiral Cyclobutanones via Nitrogen Insertion: A Concise Route to Chiral γ‐Lactams

Abstract Asymmetric access to γ‐lactams is achieved via a cyclobutanone ring expansion using widely available (1S,2R)‐1‐amino‐2‐indanol for chiral induction. Mechanistic analysis of the key N,O‐ketal rearrangement reveals a Curtin–Hammett scenario, which enables a downstream stereoinduction (up to 88:12 dr) and is corroborated by spectroscopic, crystallographic, and computational studies. In combination with an easy deprotection protocol, this operationally simple sequence allows the synthesis of a range of optically pure γ‐lactams, including those bearing all‐carbon quaternary stereocenters. In addition, the formal synthesis of drug molecules baclofen, brivaracetam, and pregabalin further …

Desymmetrisierung von prochiralen Cyclobutanonen via Stickstoffinsertion: Ein einfacher Zugang zu chiralen γ‐Lactamen

CCDC 2051971: Experimental Crystal Structure Determination

Related Article: Jan Sietmann, Mike Ong, Christian Mück-Lichtenfeld, Constantin G. Daniliuc, Johannes M. Wiest|2021|Angew.Chem.,Int.Ed.|60|9719|doi:10.1002/anie.202100642

CCDC 2051973: Experimental Crystal Structure Determination

Related Article: Jan Sietmann, Mike Ong, Christian Mück-Lichtenfeld, Constantin G. Daniliuc, Johannes M. Wiest|2021|Angew.Chem.,Int.Ed.|60|9719|doi:10.1002/anie.202100642

CCDC 2051972: Experimental Crystal Structure Determination

Related Article: Jan Sietmann, Mike Ong, Christian Mück-Lichtenfeld, Constantin G. Daniliuc, Johannes M. Wiest|2021|Angew.Chem.,Int.Ed.|60|9719|doi:10.1002/anie.202100642

CCDC 2051970: Experimental Crystal Structure Determination

Related Article: Jan Sietmann, Mike Ong, Christian Mück-Lichtenfeld, Constantin G. Daniliuc, Johannes M. Wiest|2021|Angew.Chem.,Int.Ed.|60|9719|doi:10.1002/anie.202100642