Volume 56, Issue 19 pp. 5212-5216
Communication

Asymmetric [4+2] Annulation of C1 Ammonium Enolates with Copper-Allenylidenes

Jin Song

Jin Song

Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China

These authors contributed equally to this work.

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Zi-Jing Zhang

Zi-Jing Zhang

Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China

These authors contributed equally to this work.

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Prof. Dr. Liu-Zhu Gong

Corresponding Author

Prof. Dr. Liu-Zhu Gong

Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China

Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China

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First published: 31 March 2017
Citations: 183

Graphical 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.

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.).

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