Synthesis 2014; 46(21): 2957-2964
DOI: 10.1055/s-0034-1378542
paper
© Georg Thieme Verlag Stuttgart · New York

McQuade’s Six-Membered NHC–Copper(I) Complexes for Catalytic Asymmetric­ Silyl Transfer

Lukas B. Delvos
Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany   Fax: +49(30)31428829   Email: martin.oestreich@tu-berlin.de
,
Alexander Hensel
Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany   Fax: +49(30)31428829   Email: martin.oestreich@tu-berlin.de
,
Martin Oestreich*
Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany   Fax: +49(30)31428829   Email: martin.oestreich@tu-berlin.de
› Author Affiliations
Further Information

Publication History

Received: 20 June 2014

Accepted: 29 June 2014

Publication Date:
30 July 2014 (eFirst)

Abstract

A full account of our work on enantioselective silylation of typical prochiral acceptors employing chiral six-membered NHC–copper(I) complexes introduced by McQuade and co-workers is presented. With these precatalysts, asymmetric branched-selective substitution of allylic phosphates and 1,2-addition to imines had become possible for the first time. The successful application of these catalysts in two fundamentally different reactions raised the question whether these are a privileged ligand motif for catalytic asymmetric silyl transfer. To assess their generality, these were utilized in the related 1,2-addition to aldehydes and in conjugate addition to representative α,β-unsaturated acceptors, but with limited success in both cases. This study also includes an optimization of the allylic silylation, now overcoming the limited scope of the previous protocol. The scope of the imine addition is extended to heteroaryl­-substituted aldimines.

Supporting Information

 
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