caa a22 4500 378923129 CHVBK 20180305123610.0 cr unu---uuuuu 161128e20040101xx s 000 0 eng 10.1351/pac200476030589 doi (NATIONALLICENCE)gruyter-10.1351/pac200476030589 Coordination of the Trost modular ligand to palladium allyl fragments: Oligomers, monomers and memory effects in catalysis [Elektronische Daten] [G. C. Lloyd-Jones, S. C. Stephen, I. J. S. Fairlamb, Aina Martorell, Beatriz Dominguez, P. M. Tomlin, M. Murray, J. M. Fernandez, J. C. Jeffery, T. Riis-Johannessen, Toufik Guerziz] Reaction of the C2-symmetric "Trost modular ligand" with cationic Pd(II) allyl fragments allows isolation of air- and bench-stable pro-catalysts for the asymmetric allylic alkylation of racemic cycloalkenyl esters. In solution, three distinct complexation modes are observed. When mixed in a ligand/Pd ratio of 1/2, a binuclear bis-P,O-chelate complex is generated. This species does not induce enantioselectivity in the reaction. In contrast, with a ligand/Pd ratio of 1/1, a highly enantioselective, P,P-coordinated pro-catalyst system is generated in which there are two basic coordination modes: monomeric and oligomeric. The monomeric form is mononuclear and exists as two 13-membered chelates, isomeric through loss of C2-symmetry in the ligand. The oligomeric form is polynuclear and forms chains and rings of alternating ligand and cationic Pd(allyl) units, one of which was identified by single-crystal X-ray diffraction. In solution, the monomeric and oligomeric species are in dynamic equilibrium with populations and interconversion rates controlled by concentration, temperature, and counterion. Isotopic desymmetrization analysis suggests that the monomer-oligomer equilibrium plays a crucial role in both the selectivity and efficiency of the asymmetric allylic alkylation reaction. © 2013 Walter de Gruyter GmbH, Berlin/Boston Lloyd-Jones G. C. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Stephen S. C. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Fairlamb I. J. S. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Martorell Aina The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Dominguez Beatriz The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Tomlin P. M. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Murray M. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Fernandez J. M. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Jeffery J. C. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Riis-Johannessen T. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Guerziz Toufik The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut Pure and Applied Chemistry De Gruyter 76/3(2004-01-01), 589-601 0033-4545 76:3<589 2004 76 pac https://doi.org/10.1351/pac200476030589 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1351/pac200476030589 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lloyd-Jones G. C. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Stephen S. C. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Fairlamb I. J. S. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Martorell Aina The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Dominguez Beatriz The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Tomlin P. M. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Murray M. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Fernandez J. M. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Jeffery J. C. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Riis-Johannessen T. The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 700 1- Guerziz Toufik The Bristol Centre for Organometallic Catalysis, School of Chemistry, The University of Bristol, Cantock 's Close, Bristol, BS8 1TS, UK aut NATIONALLICENCE 773 0- Pure and Applied Chemistry De Gruyter 76/3(2004-01-01), 589-601 0033-4545 76:3<589 2004 76 pac CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter