Synlett 2012; 23(15): 2231-2236
DOI: 10.1055/s-0032-1316737
letter
© Georg Thieme Verlag Stuttgart · New York

Some Practical Methods for the Application of 5-Metallo-1-benzyl-1H-tetrazoles in Synthesis

Sean H. Wiedemann*
a   Amgen, Inc., Chemical Process R&D, 360 Binney Street, Cambridge, MA 02142, USA
,
Matthew M. Bio*
b   Amgen, Inc., Chemical Process R&D, One Amgen Center Drive, Thousand Oaks, CA 91320-1799, USA, Fax: +1(617)4443916   eMail: sean.wiedemann@amgen.com
,
Liane M. Brown
a   Amgen, Inc., Chemical Process R&D, 360 Binney Street, Cambridge, MA 02142, USA
,
Karl B. Hansen
a   Amgen, Inc., Chemical Process R&D, 360 Binney Street, Cambridge, MA 02142, USA
,
Neil F. Langille
a   Amgen, Inc., Chemical Process R&D, 360 Binney Street, Cambridge, MA 02142, USA
› Institutsangaben
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Publikationsverlauf

Received: 26. März 2012

Accepted after revision: 01. Juli 2012

Publikationsdatum:
17. August 2012 (online)


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Abstract

Nucleophilic reagents such as 5-lithiotetrazoles are synthetically powerful tools for the installation of tetrazole functional groups, but they are of limited utility due to the instability of tetrazole-derived carbanions. Herein, we report practical methods for the generation and use of new 5-metallo-1-benzyl-1H-tetrazoles (M = K, MgX, ZnX) derived from either 1-benzyl-1H-tetrazole or 1-benzyl-5-bromo-1H-tetrazole. By varying the metal counterion, the tetrazole carbanion stability was improved. Potassium- and magnesium-derived reagents underwent additions to carbonyl ­compounds at –30 and –20 °C, respectively. The isolated yields (41–85%) from these and other reactions were comparable to those reported for 5-lithiotetrazoles at much lower temperatures (–78 to –98 °C).

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