Synthesis 2016; 48(20): 3603-3617
DOI: 10.1055/s-0035-1562434
paper
© Georg Thieme Verlag Stuttgart · New York

Base-Promoted Carbocyclization Reactions of α-Substituted N-(2-Alkynylphenyl)acetamides

Yan-Jhu Chen
Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 70101, ROC   Email: cpchuang@mail.ncku.edu.tw
,
Che-Ping Chuang*
Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 70101, ROC   Email: cpchuang@mail.ncku.edu.tw
› Author Affiliations
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Publication History

Received: 28 March 2016

Accepted after revision: 03 May 2016

Publication Date:
22 June 2016 (online)


Abstract

A synthetic method for highly functionalized quinolin-2(1H)-ones has been developed. The copper(II) chloride-catalyzed aerobic oxidative carbocyclization reactions of α-substituted N-[2-(phenylethynyl)phenyl]acetamides, via the Conia-ene-type intramolecular carbocupration onto the alkynyl moiety, produced 3,4-difunctionalized quinolin-2(1H)-ones. In the absence of copper(II) chloride, these α-substituted acetamides undergo base-promoted nucleophilic 6-exo-dig carbocyclization to generate 3-functionalized quinolin-2(1H)-ones. Several useful functional groups including benzoyl, alkanoyl, diethoxyphosporyl, cyano, and methoxycarbonyl groups are compatible with the reaction conditions. α-Substituted N-(2-ethynylphenyl)acetamides bearing a terminal C≡C bond could also be used to generate the corresponding 4-methyl-substituted quinolin-2(1H)-ones smoothly.

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