Synthesis 2009(18): 3143-3149  
DOI: 10.1055/s-0029-1216901
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

A ‘Click’ Approach to the Synthesis of 3-[2-(1-Alkyltriazol-4-yl)ethyl]indoles

Marino Petrini*, Rafik R. Shaikh
Dipartimento di Scienze Chimiche, Università di Camerino, Via S. Agostino 1, 62032 Camerino, Italy
Fax: +39(0737)402297; e-Mail: marino.petrini@unicam.it;
Further Information

Publication History

Received 30 April 2009
Publication Date:
14 July 2009 (online)

Abstract

Copper-catalyzed cycloaddition of N-(tert-butoxycarbonyl)-3-(1-tosyl-3-butynyl)-1H-indole with various azides readily provides the corresponding (triazolylethyl)indoles. These derivatives can be regarded as indole-3-propionic acid mimics because of the electronic features of the triazole ring that are closely related to the amido group. The obtained (indolylethyl)triazoles can be further functionalized exploiting an elimination-addition reaction involving the tosyl group.

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Thus, the presence of the first triazolyl group would provide a sort of activation for the formation of the second group, as evidenced by Finn and co-workers;¹7 however, this activation is not strong enough to provide complete formation of the bisadduct unless a large excess of alkyne is used.