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Synfacts 2009(3): 0292-0292  
DOI: 10.1055/s-0028-1087759
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart ˙ New York

Kinetic Studies of Palladium-Catalyzed Tsuji-Trost Allylations

Contributor(s): Mark Lautens, Praew Thansandote
L. A. Evans, N. Fey, J. N. Harvey, D. Hose, G. C. Lloyd-Jones*, P. Murray, A. G. Orpen, R. Osborne, G. J. J. Owen-Smith, M. Purdie
University of Bristol, AstraZeneca, Bristol and AstraZeneca, Loughborough, UK
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Publication History

Publication Date:
19 February 2009 (online)

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Significance

The authors studied the effect of varying the electronic properties of phosphine ligands in palladium-catalyzed allylations. They observed a counterintuitive result: while electron-withdrawing palladium-phosphine complexes are more susceptible to nucleophilic attack, they gave lower turnover compared to electron-donating ­analogues. With the help of cross-over experiments, NMR spectroscopy studies, and kinetic experiments, the authors hypothesized that electron-withdrawing ligands increase the occurrence of ion-pair return (see above) contributing to lower turnover. These findings provide important insights into enantioselective allylations.