Asymmetric [4+2] Annulation of C1 Ammonium Enolates with Copper‐Allenylidenes. Issue 19 (31st March 2017)

• Record Type: Journal Article
• Authors: Song, Jin; Zhang, Zi‐Jing; Gong, Liu‐Zhu
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 19(2017)
• Page Start: 5212
• Page End: 5216
• Publication Date: 2017-03-31
• Subjects: [4+2] annulations -- C1 ammonium enolates -- cooperative catalysis -- copper -- heterocycles; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201700105
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: An asymmetric catalytic decarboxylative [4+2] annulation of 4‐ethynyl dihydrobenzooxazinones and carboxylic acids has been established by cooperative copper and nucleophilic Lewis base catalysis. A C1 ammonium enolate and copper–allenylidene complex, each catalytically generated from different substrates, underwent a cascade asymmetric propargylation and lactamization process to yield optically active 3, 4‐dihydroquinolin‐2‐one derivatives with excellent levels of stereoselectivity (up to 99 % ee, 95:5 d.r.). Abstract : A team effort : An asymmetric [4+2] annulation of C1 ammonium enolates with copper–allenylidenes catalytically generated from carboxylic acids and 4‐ethynyl dihydrobenzooxazinones, respectively, led to optically active 3, 4‐dihydroquinolin‐2‐one derivatives with excellent levels of stereoselectivity.