Synthesis 2015; 47(04): 511-516
DOI: 10.1055/s-0034-1379458
paper
© Georg Thieme Verlag Stuttgart · New York

A Study of Negishi Cross-Coupling Reactions with Benzylzinc Halides­ To Prepare Original 3-Ethoxypyrazoles

Eloi P. Coutant
a   Unité de Chimie et Biocatalyse, Département de Biologie Structurale et Chimie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France   Fax: +33(1)45686404   Email: yves.janin@pasteur.fr
b   Unité Mixte de Recherche 3523, Centre National de la Recherche Scientifique, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
,
Yves L. Janin*
a   Unité de Chimie et Biocatalyse, Département de Biologie Structurale et Chimie, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France   Fax: +33(1)45686404   Email: yves.janin@pasteur.fr
b   Unité Mixte de Recherche 3523, Centre National de la Recherche Scientifique, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
› Author Affiliations
Further Information

Publication History

Received: 01 October 2014

Accepted after revision: 24 October 2014

Publication Date:
21 November 2014 (online)


Abstract

The Negishi palladium-catalyzed cross-coupling reaction between 3-ethoxy-4-iodo-1H-pyrazole and various benzylzinc halides was extensively studied. Using simplified, robust, and optimized reaction conditions, a series of electron-poor benzylzinc halides were prepared and used to synthesize 4-benzyl-3-ethoxy-1H-pyrazoles derivatives. From these, iodination on C5 of the pyrazole nucleus led to the corresponding 4-benzyl-3-ethoxy-5-iodo-1H-pyrazoles, these are original building blocks for the preparation of libraries of new chemical entities.

Supporting Information