The Newman-Kwart Rearrangement of O-Aryl Thiocarbamates: Substantial Reduction in Reaction Temperatures through Palladium Catalysis
Jeremy N. Harvey, Jesús Jover, Guy C. Lloyd-Jones*, Jonathan D. Moseley, Paul Murray, Joseph S. Renny
*School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK), Email: guy.lloyd-jonesbris.ac.uk
J. N. Harvey, J. Jover, G. C. Lloyd-Jones, J. D. Moseley, P. Murray, J. S. Renny, Angew. Chem. Int. Ed., 2009, 48, 7612-7615.
DOI: 10.1002/anie.200903908 (free Supporting Information)
The Newman-Kwart rearrangement normally requires high temperatures (200-300°C), but in the presence of Pd(PtBu)2 proceeds smothly at 100°C with a range of substrates. The reaction proceeds through a five-centred Pd-S coordinated oxidative addition, with intermolecular exchange of aryl and thiocarbamate moieties through dimerization of the resting state
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Working model for Pd-catalyzed NKR of 1a to 2a. Numbers in
parenthesis are DFT-derived ZPE corrected energies in kcal • mol-1
Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.
Newman-Kwart Rearrangement, homogeneous catalysis, palladium, reaction mechanism, rearrangement, sulfur compounds