2006 Fiscal Year Final Research Report Summary
Transition Metal Catalysis in Water
| Project/Area Number |
14078223
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Institute for Molecular Science (2004-2005)
Okazaki National Research Institutes (2002-2003) |
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Principal Investigator |
UOZUMI Yasuhiro Institute for Molecular Science, Research Center for Molecular-scale Nanoscience, Professor, 分子スケールナノサイエンスセンター, 教授 (90201954)
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| Project Period (FY) |
2002 – 2005
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| Keywords | aquacatalysis / transition metal / organic synthesis / stereoselectivity / pincer complex |
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| Research Abstract |
Organometallic pincer complexes containing terdentate monoanionic ligands composed of an anionic aryl carbon atom and two mutually trans-chelating donosites at the 2,6-positions of the aromatic ring have been attracting widespread interest in catalysis and material science. A wide range of NCN pincer palladium complexes, [4-tert-2,6-bis(N-alkylimino)phenyl]chloropalladium (alkyl = n-butyl, benzyl, cyclohexyl, t-butyl, adamantyl, phenyl, 4-methoxyphenyl), were readily prepared from trans-(4-tert-butyl-2, 6-diformyl-phenyl)chlorobis(triphenylphosphine)palladium via dehydrative introduction of the corre sponding alkylimino ligand groups (ligand introduction route) in excellent yields (71-98%). NMR studies on this route for forming pincer complexes revealed the intermediacy of [4-tert-2,6- bis(N-alkylimino)phenyl]chlorobis(triphenylphosphine)palladium which is in equilibrium with the corresponding NCN pincer complexes via coordination/dissociation of the intramolecular imino groups and triphenylphosphine ligands.
Nitromethane was safely applied as a Cl nucleophile for palladium-catalyzed p-allylic substitution in water with amphiphilic PS-PEG resin-supported phosphine-palladium complexes. Catalytic asymmetric nitromethylation of cycloalkenyl esters was achieved in water as a single reaction medium under heterogeneous conditions using 5 mol % palladium of a PS-PEG resin-supported pallad ium-imidazoindolephosphine complex to give optically active (cycloalkenyl) nitromethanes with up to 98% ee. Water-based aerobic oxidation of alcohols and alfa-alkylation of methyl ketones with a variety of alcohols as alkylation reagents were also successfully achieved by using the amphiphilic resin-dispersion of nanometal (Pd, Pt) particle-catalysts.
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