DEVELOPMENT OF NEW SYNTHETIC REACTIONS BY USING THE PROPERTIES OF SELENOCARBONYL GROUP

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The development of new synthetic reactions with high efficiency and selectivity is one of the most important issues in synthetic organic chemistry. The acceleration and reduction of synthetic process from the starting materials to the final products are also of important. A variety of reactions utilizing the ability of double bonds involving the carbon atoms have been known. If the compounds bearing the weak double bonds with the carbon atom are designed and easily handled, unprecedented synthetic reactions under milder reaction conditions for shorter reaction times would be realized. The prime objective of the present research was to explore synthetic reactions on the basis of the higher reactivity of the double bonds between the carbon atom and the selenium atom, which was found in the forth law of the periodic table of elements.As a result, the use of selenium isologues of amides, i.e., selenoamides provided new types of reactions, and their scope and limitations were disclosed as follows.・Addition reaction of selenium isologues of enolate ions, i.e., eneselenolates to aldehydes smoothly proceeded to give b-hydroxy selenoamides. The selenoamides bearing benzyl groups on the nitrogen atom exhibited high stereoselectivity.・Methylation of selenoamides with methyl triflate was complete within one sec to produce selenoiminium salts. The alkynylation of selenoiminium salts took place to give α,β-unsaturated ketones in good to high yields.・The reaction of α-silyl selenoacetamides with aldehydes furnished α,β-unsaturated selenoamdies with E-selectivity. The application of this reaction led to selenoamides bearing long olefinic groups.