Synthesis 2012(6): 920-926  
DOI: 10.1055/s-0031-1289722
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of 1,3-Dihydrobenzo[c]thiophene-imines via Tandem Reactions of o-(1-Alkynyl)benzamides and Lawesson’s Reagent

Qiuping Ding*a, Xianjin Liua, Hongming Wangb, Min Chena, Yiyuan Peng*a
a Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Chemistry and Chemical Engineering, Jiangxi Normal University, 99 Ziyang Road, Nanchang 330022, P. R. of China
Fax: +86(791)88120396; e-Mail: dqpjxnu@gmail.com; e-Mail: yiyuanpeng@yahoo.com;
b Institute for Advanced Study, Nanchang University, Nanchang, 330031, P. R. of China
Further Information

Publication History

Received 8 November 2011
Publication Date:
27 February 2012 (online)

Abstract

Metal-free, one-pot tandem reactions of o-(1-alkyn­yl)benzamides proceed smoothly in the presence of Lawesson’s reagent­ leading to 1,3-dihydrobenzo[c]thiophene-imine derivatives in moderate to excellent yields under mild conditions. The method is highly regiospecific for the o-(1-alkynyl)benzothioamide, and only the five-membered-ring product is generated via a 5-exo-dig cyclization involving the sulfur atom.