Two flavors of PEPPSI-IPr: activation and diffusion control in a single NHC-ligated Pd catalyst?
Two flavors of PEPPSI-IPr: activation and diffusion control in a single NHC-ligated Pd catalyst?
Abnormal reactivity has been observed in Negishi, Suzuki?Miyaura, and Kumada?Tamao?Corriu cross-couplings in which PEPPSI-IPr (where PEPPSI stands for pyridine enhanced precatalyst preparation, stabilization, and initiation and IPr refers to the NHC ligand) is employed, implicating the presence of two distinct Pd0 species in the catalytic cycle. Polybrominated arenes and organometallic reagents react selectively to give the product of exhaustive polysubstitution regardless of the initial reaction stoichiometry. Competition experiments suggest that, after an initial activation controlled oxidative addition, reductive elimination produces an ultrareactive Pd0 species which consumes all remaining C?Br bonds in the molecule under diffusion control.
146-149
Larrosa, Igor
6ab25161-9d87-4f15-8559-0c0e59810989
Somoza, Clara
95e7004e-46d2-40e4-ab96-9e98e1ada2e7
Banquy, Alexandre
302e336d-c006-4b4e-9c52-340d1979a552
Goldup, Stephen M.
0a93eedd-98bb-42c1-a963-e2815665e937
6 December 2011
Larrosa, Igor
6ab25161-9d87-4f15-8559-0c0e59810989
Somoza, Clara
95e7004e-46d2-40e4-ab96-9e98e1ada2e7
Banquy, Alexandre
302e336d-c006-4b4e-9c52-340d1979a552
Goldup, Stephen M.
0a93eedd-98bb-42c1-a963-e2815665e937
Larrosa, Igor, Somoza, Clara, Banquy, Alexandre and Goldup, Stephen M.
(2011)
Two flavors of PEPPSI-IPr: activation and diffusion control in a single NHC-ligated Pd catalyst?
Organic Letters, 13 (1), .
(doi:10.1021/ol1027283).
(PMID:21133362)
Abstract
Abnormal reactivity has been observed in Negishi, Suzuki?Miyaura, and Kumada?Tamao?Corriu cross-couplings in which PEPPSI-IPr (where PEPPSI stands for pyridine enhanced precatalyst preparation, stabilization, and initiation and IPr refers to the NHC ligand) is employed, implicating the presence of two distinct Pd0 species in the catalytic cycle. Polybrominated arenes and organometallic reagents react selectively to give the product of exhaustive polysubstitution regardless of the initial reaction stoichiometry. Competition experiments suggest that, after an initial activation controlled oxidative addition, reductive elimination produces an ultrareactive Pd0 species which consumes all remaining C?Br bonds in the molecule under diffusion control.
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Published date: 6 December 2011
Organisations:
Organic Chemistry: Synthesis, Catalysis and Flow
Identifiers
Local EPrints ID: 370657
URI: http://eprints.soton.ac.uk/id/eprint/370657
ISSN: 1523-7060
PURE UUID: 9c79f210-3eed-4a6a-8ac2-3ccb11f04441
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Date deposited: 03 Nov 2014 13:27
Last modified: 14 Mar 2024 18:20
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Author:
Igor Larrosa
Author:
Clara Somoza
Author:
Alexandre Banquy
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