Synthesis 2014; 46(24): 3374-3382
DOI: 10.1055/s-0034-1379110
paper
© Georg Thieme Verlag Stuttgart · New York

Manganese(III) Acetate Mediated Oxidative Free-Radical Reactions of 2-(Alkenylamino)-1,4-naphthoquinones with 1,3-Dicarbonyl Compounds

Yu-Lin Hsu
Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 70101, ROC   Fax: +886(6)2740552   Email: cpchuang@mail.ncku.edu.tw
,
Che-Ping Chuang*
Department of Chemistry, National Cheng Kung University, Tainan, Taiwan 70101, ROC   Fax: +886(6)2740552   Email: cpchuang@mail.ncku.edu.tw
› Author Affiliations
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Publication History

Received: 29 July 2014

Accepted: 19 August 2014

Publication Date:
24 September 2014 (online)


Abstract

The manganese(III)-mediated oxidative free-radical reactions of 2-(alkenylamino)-1,4-naphthoquinones are described. The free-radical reaction of 2-(allylamino)-1,4-naphthoquinone with 1,3-dicarbonyl compounds provides a novel method for the synthesis of benzo[f]indole-4,9-diones and benzo[g]quinoline-5,10-diones. The reaction shows high chemoselectivity, depending on the solvents and 1,3-dicarbonyl compounds used. With both 1,3-diones and β-keto esters, in acetic acid, the condensation products, benzo[f]indoles, were generated selectively; in acetonitrile, the [5+1]-cyclization products, benzo[g]quinolines and tetrahydrobenzo[g]quinolines, were produced in high chemoselectivity. With diethyl malonate, the [5+1]-cyclization product, the corresponding tetrahydrobenzo[g]quinoline, was produced exclusively. The free-radical reaction of a 2-(vinylamino)-1,4-naphthoquinone with 1,3-dicarbonyl compounds produced benzo[g]quinolines effectively.

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