Issue 29, 2012

Stereospecific synthesis and catalytic activity of l-histidylidene metal complexes

Abstract

We report on the synthesis, metal coordination, and catalytic impact of histidylidene, a histidine-derived N-heterocyclic carbene (NHC) ligand. The histidinium salt 3, comprising methyl substituents at both heterocyclic nitrogens and protected at the C- and N-terminus of the amino acid, was rhodated and iridated by a transmetallation protocol using Ag2O. Ambient temperature and short reaction times were pivotal for full retention of configuration at the α-carbon. The stereospecificity of the reaction was conveniently probed by 31P NMR spectroscopy after transmetallation with rhodium(I) and coordination of enantiopure (S)-Ph-binepine. The histidylidene rhodium complexes are highly efficient catalysts for the mild hydrosilylation of ketones. For the cationic complexes [Rh(cod)(histidylidene)(phosphine)]+, lowering the temperature shifted the rate-limiting step of the catalytic reaction to an earlier stage that is not enantioselective. Hence the asymmetric induction—which is governed by the chiral phosphine—did not improve at low temperature.

Graphical abstract: Stereospecific synthesis and catalytic activity of l-histidylidene metal complexes

Supplementary files

Article information

Article type
Paper
Submitted
13 Apr 2012
Accepted
16 May 2012
First published
16 May 2012

Dalton Trans., 2012,41, 8813-8821

Stereospecific synthesis and catalytic activity of L-histidylidene metal complexes

A. Monney, E. Alberico, Y. Ortin, H. Müller-Bunz, S. Gladiali and M. Albrecht, Dalton Trans., 2012, 41, 8813 DOI: 10.1039/C2DT30799E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements