Study of the correlation between the structure of auxiliary ligands for transition metal complexes as catalysts and the selectivity in homogeneous catalytic reactions

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According to the proposed project, the Rh(I)-catalyzed hydroformylation, Pd(0)-catalyzed allylation reaction, and conjugate addition of various organozincates were carried out. Especially, the ligand effects on the chemo-, regio-, as well as stereoselectivity in these reactions were elucidated in terms of both steric and electronic origin. Thus, the report consists of the following items ;1. Novel auxiliary ligands for rhodium(I) complexes and their selectivity in hydroformylation of alkenes-With use of the chiral, chelating phsophorus ligands (L-L) having a wide bite angle (-120ﾟ), [RhH(CO)_2L-L] exhibited high catalytic activity in the hydroformylation of vinylarenes, but with low enantioselectivity.2. Regio- and stereoselectivity in palladium(0)-catalyzed allylation-Pd(0)-catalyzed allylation of 2,7-octadienyl acetate gave rise to a novel five-membered ring formation which crucially relied on acetic acid as a solvent. The novel cyclization via pi-allylpalladium intermediates with stereospecific 1,3-chirality transmission was realized in certain prostaglandin synthesis.3. Conjugate addition of functionalized organozincates and their applications to organic syntheses-Diastereoselective addition of particular(Z)-vinylzincates to 4-alkoxy-2-cyclopentenone, followed by an enolate trapping with propargylic iodide, completed the prostaglandin synthesis.