Mechanistic insights into the Pd-catalyzed direct amination of allyl alcohols: evidence for an outer-sphere mechanism involving a palladium hydride intermediate

Supaporn Sawadjoon; Per J R Sjöberg; Andreas Orthaber; Olle Matsson; Joseph S M Samec

doi:10.1002/chem.201303431

Mechanistic insights into the Pd-catalyzed direct amination of allyl alcohols: evidence for an outer-sphere mechanism involving a palladium hydride intermediate

Chemistry. 2014 Feb 3;20(6):1520-4. doi: 10.1002/chem.201303431. Epub 2014 Jan 8.

Authors

Supaporn Sawadjoon¹, Per J R Sjöberg, Andreas Orthaber, Olle Matsson, Joseph S M Samec

Affiliation

¹ Department of Chemistry, BMC, Uppsala University, Box 576, 751 23 Uppsala (Sweden), Fax: (+46) 18-4714988.

PMID: 24403056
DOI: 10.1002/chem.201303431

Abstract

The mechanism of direct amination of allyl alcohol by a palladium triphenylphosphite complex has been explored. Labelling studies show that the reaction proceeds through a π-allylpalladium intermediate. A second-order dependence of reaction rate on allyl alcohol concentration was observed. Kinetic isotope effect studies and ESI-MS studies are in agreement with a reaction proceeding through a palladium hydride intermediate in which both O-H bond and C-O bond cleavages are involved in rate-determining steps. A stereochemical study supports an outer-sphere nucleophilic attack of the π-allylpalladium intermediate giving complete chiral transfer from starting material to product.

Keywords: alcohols; allylation; kinetics; palladium; reaction mechanisms.