Development of Sustainable Process for Molecular Transformation Using Lewis Acid/Transition Metal Catalysts

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Stereocontroll via σ-π chelation was achieved by using group 13 Lewis acids. During this study, we found that some palladium (II) species act not only as transition metal catalyst but also as Lewis acid catalyst. Based on this finding, total syntheses of natural products, BCH-2051 and vibsanol, were achieved. Furthermore, antibiotics, (+)-ochromycinoneand (+)-rubiginone B2, were synthesized by using novel Au catalyst.Asymmetric allylation of imine derivatives was achieved by using optically active bis-π-allylpalladium, and the reaction was applied to the preparation of a synthetic intermediate of DMP-777. As a related reaction, novel synthetic method for cyanoindoles via three component coupling was developed. We found that the intramolecular reaction of amines and alkynes give nitrogen heterocycles in the presence of palladium/acetic acid catalyst. This reaction was applied to the total synthesis of an alkaloid, 209D.α-Allylation of hetero-aromatics and ketones were achieved by using methylenecyclopropane and palladium catalyst. On the other hand, the reaction with methyleneaziridine provided pyrrole derivatives having a pyridine or benzene ring.Total syntheses of marine polycyclic ethers, gambierol and brevetoxin B, were achieved via the intramolecular allylation followed by ring-closing metathesis.