Synlett 2013; 24(15): 2021-2022
DOI: 10.1055/s-0033-1339685
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© Georg Thieme Verlag Stuttgart · New York

Toluenesulfonyl Cyanide (TsCN)

Xiang Fei
Department of Chemistry, University of Nebraska, Lincoln, ­Nebraska 68588-0304, USA   Email: [email protected]
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Further Information

Publication History

Publication Date:
21 August 2013 (online)

Introduction

Toluenesulfonyl cyanide (TsCN) is a convenient and versatile cyanide source that has great potential in organic synthesis. It displays useful reactivity for electrophilic cyanation of aromatic compounds,[1] carbonyl compounds,[2] and other types of organic compounds.[3] It has been used in radical-mediated cyanation[4] and hydrocyanation[5] reactions. Furthermore, TsCN has been reported to be a good component for [4+2][6] and [3+2][7] cycloaddition reactions. The sulfonyl tetrazoles produced from 1,3-dipolar cycloaddition of TsCN with azides can be further elaborated using nucleophilic aromatic substitution (SNAr). This two-step process represents an interesting ligation strategy that probably warrants greater exploration in chemical biology.[8] Other uses of TsCN in the recent literature include reactions with allylic alcohols to make allyl sulfones,[9] and palladium-catalyzed C–H activation of arenes to synthesize diaryl sulfides.[10]

TsCN is a white crystalline solid (mp 49–50 °C) that is available from dozens of commercial sources. It can be readily prepared in the lab by several methods (Scheme [1]).[11] Compared to other commonly used CN+ equivalents, such as cyanogen bromide [LD50 (rats, orally) = 25–50 mg/kg],[12] TsCN is less toxic [LD50 (rats, orally) = 800–1000 mg/kg][13] and has a longer shelf life. Hence, TsCN will likely continue to serve as an important and versatile reagent for ­organic synthesis.

Zoom Image
Scheme 1 Cox and Ghosh’s synthesis of toluenesulfonyl cyanide[11b]
 
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