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Synthesis 2009(23): 3989-3993  
DOI: 10.1055/s-0029-1217028
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Preparation of α,β-Unsaturated Lactams through Intramolecular Electrophilic Carbamoylation of Alkenes

Yoshizumi Yasuia, Issei Kakinokiharab, Hiroshi Takedab, Yoshiji Takemoto*b
a WPI Advanced Institute for Materials Research, Tohoku University, Aoba, Sendai 980-8577, Japan
b Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
Fax: +81(75)7534569; e-Mail: takemoto@pharm.kyoto-u.ac.jp;
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Publication History

Received 10 June 2009
Publication Date:
12 October 2009 (online)

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Abstract

A general synthetic method for the preparation of α,β-unsaturated lactams starting from alkenylchloroformamides has been developed. The reaction was complete within five minutes at 150 ˚C in N-methylpyrrolidone with a catalytic amount of HBr under microwave irradiation. Not only six-membered lactams, but also five- and seven-membered lactams were obtained in high yields.

Key words

lactam - cyclization - electrophilic addition - acid catalyst - microwave