Scope and limitations of ether-directed, metal-catalysed aza-Claisen rearrangements; improved stereoselectivity using non-coordinating solvents

Jamieson, A. G. and Sutherland, A. (2006) Scope and limitations of ether-directed, metal-catalysed aza-Claisen rearrangements; improved stereoselectivity using non-coordinating solvents. Organic and Biomolecular Chemistry, 4, pp. 2932-2937. (doi: 10.1039/b607014k) (PMID:16855742)

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Abstract

In an effort to understand and enhance the stereochemical outcome of the MOM-ether directed rearrangement of allylic trichloroacetimidates we have investigated various reaction conditions for this process. A range of Pd(II) and other metal catalysts have been shown to effectively catalyse the rearrangement providing the subsequent allylic amides in high selectivity (up to 11 : 1 ratio of diastereomers). The replacement of THF as a solvent in this reaction with non-coordinating solvents such as toluene has led to an enhancement of the directing effect resulting in a significant increase in the diastereoselective outcome (15 : 1 ratio). The reaction was also carried out for the first time, using a highly coordinating ionic solvent which disrupts binding of the Pd(II)-catalyst to the MOM-ether yielding the allylic amide in only moderate diastereoselectivity. These results provide further evidence for the ether directed aza-Claisen rearrangement of allylic trichloroacetimidates.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Jamieson, Dr Andrew and Sutherland, Professor Andrew
Authors: Jamieson, A. G., and Sutherland, A.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Organic and Biomolecular Chemistry
Publisher:Royal Society of Chemistry
ISSN:1477-0520
ISSN (Online):1477-0539
Published Online:30 June 2006

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