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Synlett 2010(14): 2202-2203  
DOI: 10.1055/s-0030-1258019
SPOTLIGHT
© Georg Thieme Verlag Stuttgart ˙ New York

Thiophenol-Mediated Radical Cyclizations

Shovan Mondal*
Department of Chemistry, Kalyani University, Kalyani 741235, West Bengal, India
e-Mail: shovanku@gmail.com;
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Publication History

Publication Date:
13 August 2010 (online)

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Introduction

Thiophenol (PhSH, CAS: 108-98-5-Y) is a commercially available organosulfur compound. Recently thiophenol-mediated radical cyclizations become highlighted for the construction of heterocycles due to the cost-effective, tin-free methodology. These radical reactions proceed via the formation of a carbon-centered radical species generated by the addition of a sulfanyl radical to an unsaturated bond and a subsequent intramolecular addition of the resulting carbon-centered radical to another multiple bond, followed by the abstraction of hydrogen from thiophenol to afford the product (Scheme  [¹] a). Otherwise, the sulfanyl radical, generated from thiophenol and radical initiator, adds to the terminus of the triple bond to generate an al­kenyl radical, which undergoes a 1,5-hydrogen atom transfer (HAT). After translocation, the new radical species can cyclize intramolecularly to give a cyclopentane derivative (Scheme  [¹] b).

Scheme 1