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dc.contributor.authorNeuwald, Boris
dc.contributor.authorCaporaso, Lucia
dc.contributor.authorCavallo, Luigi
dc.contributor.authorMecking, Stefan
dc.date.accessioned2015-08-03T10:58:28Z
dc.date.available2015-08-03T10:58:28Z
dc.date.issued2013-01-09
dc.identifier.issn00027863
dc.identifier.pmid23256526
dc.identifier.doi10.1021/ja3101787
dc.identifier.urihttp://hdl.handle.net/10754/562615
dc.description.abstractVarious phosphinesulfonato ligands and the corresponding palladium complexes [{((PaO)PdMeCl)-μ-M}n] ([{( X1-Cl)-μ-M}n], (PaO) = κ2- P,O-Ar2PC6H4SO2O) with symmetric (Ar = 2-MeOC6H4, 2-CF3C6H4, 2,6-(MeO)2C6H3, 2,6-(iPrO)2C 6H3, 2-(2′,6′-(MeO)2C 6H3)C6H4) and asymmetric substituted phosphorus atoms (Ar1 = 2,6-(MeO)2C6H 3, Ar2 = 2′-(2,6-(MeO)2C 6H3)C6H4; Ar1 = 2,6-(MeO)2C6H3, Ar2 = 2-cHexOC 6H4) were synthesized. Analyses of molecular motions and dynamics by variable temperature NMR studies and line shape analysis were performed for the free ligands and the complexes. The highest barriers of ΔGa = 44-64 kJ/mol were assigned to an aryl rotation process, and the flexibility of the ligand framework was found to be a key obstacle to a more effective stereocontrol. An increase of steric bulk at the aryl substituents raises the motional barriers but diminishes insertion rates and regioselectivity. The stereoselectivity of the first and the second methyl acrylate (MA) insertion into the Pd-Me bond of in situ generated complexes X1 was investigated by NMR and DFT methods. The substitution pattern of the ligand clearly affects the first MA insertion, resulting in a stereoselectivity of up to 6:1 for complexes with an asymmetric substituted phosphorus. In the consecutive insertion, the stereoselectivity is diminished in all cases. DFT analysis of the corresponding insertion transition states revealed that a selectivity for the first insertion with asymmetric (P aO) complexes is diminished in the consecutive insertions due to uncooperatively working enantiomorphic and chain end stereocontrol. From these observations, further concepts are developed. © 2012 American Chemical Society.
dc.publisherAmerican Chemical Society (ACS)
dc.titleConcepts for stereoselective acrylate insertion
dc.typeArticle
dc.contributor.departmentChemical Science Program
dc.contributor.departmentKAUST Catalysis Center (KCC)
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalJournal of the American Chemical Society
dc.contributor.institutionDepartment of Chemical Materials Science, Department of Chemistry, University of Konstanz, 78464 Konstanz, Germany
dc.contributor.institutionDepartment of Chemistry and Biology, University of Salerno, Via Ponte Don Melillo, 84084-Fisciano (SA), Italy
kaust.personCavallo, Luigi
dc.relation.issupplementedbyDOI:10.5517/ccz2ddt
dc.relation.issupplementedbyDOI:10.5517/ccz2dcs
display.relations<b> Is Supplemented By:</b> <br/> <ul><li><i>[Dataset]</i> <br/> Neuwald, B., Caporaso, L., Cavallo, L., & Mecking, S. (2013). CCDC 896036: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/ccz2ddt. DOI: <a href="https://doi.org/10.5517/ccz2ddt">10.5517/ccz2ddt</a> HANDLE: <a href="http://hdl.handle.net/10754/624743">10754/624743</a></li><li><i>[Dataset]</i> <br/> Neuwald, B., Caporaso, L., Cavallo, L., & Mecking, S. (2013). CCDC 896035: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/ccz2dcs. DOI: <a href="https://doi.org/10.5517/ccz2dcs">10.5517/ccz2dcs</a> HANDLE: <a href="http://hdl.handle.net/10754/624742">10754/624742</a></li></ul>
dc.date.published-online2013-01-09
dc.date.published-print2013-01-23


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