Creation of Highly Functional Reagents and its Application to Novel Organic Synthesis

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The following results are obtained in this research project.1.Manganese Ate Complexes as a New Reducing Agent : Perfectly Regiocontrolled Generation and Reactions of the Mn-Enolates with ElectrophilesManganese (II) ate complexes cleanly react with carbonyl compounds bearing a leaving group at the alpha position to generate the enolates of the original ketones, esters, and amides, irrespective of their structure, where the manganate serves as a reductant not an alkylation agent. In this reductive generation of the enolates based on the novel reactivity of the manganese ate complexes, a kind of oxidative addition of a substrate to the ate complex and the reductive elimination of the ligands on manganese are possibly involved as the key processes, while the process equivalent to "metal-halogen exchange" does not seem to be significant. The generality of this reaction was demonstrated in the generation of the enolates of not only aromatic ketones and aliphatic ketones but also an aliphatic … More ester and amide. As for the synthetic value, this reaction was successfully applied to the perfectly regiospecific generation and reactions of a pair of the regioisomeric enolates corresponding to the unsymmetrical and non-branched aliphatic ketones.2.Unprecedented Samarium-Mediated Reactions : Generation of Non-Stabilized Carbonyl YlidsSamarium reveals a strong reducing ability and by virtue of this character together with its oxophilicity, is widely applied to organic synthesis in the formation of carbon-carbon bonds and transformation of a variety of functionalities with high selectivities. In the course of our study on the generation and reactions of reactive species, we report herein the generation of novel active species, non-stabilized carbonyl ylids from iodomethyl silyl ethers mediated by samarium, otherwise inaccessible, and their [3+2] cycloadditions to a variety of unsaturated compounds such as aldehydes, alkenes, allenes, and alkynes.3.Silicon-Directed Cyclization of Vinylsilanes Bearing Hydroxy Group Catalyzed by an AcidThe acid-catalyzed cyclization of vinylsilanes bearing a hydroxy group took place cleanly to give tetrahydrofurans and tetrahydropyrans, and the addition of hydroxy group to vinylsilane proceeded in a syn stereoselective fashion. Less