有機遷移金属錯体に関する研究

Abstract

This article deals with three topics from organic syntheses by transition metal complexes ; (1) synthesis via cobaltacycles, (2) synthesis using isonitrile, and (3) rhodium carbonyl cluster catalysis.(1) CpCo (PPh3) 2 stepwisely reacted with acetylene to give π-acetylene cobalt and cobaltacyclopentadiene complexes. The former also gave 4- and 5-membered cobaltacycles by the reaction with isocyanide, carbon disulfide and olefin. Cobaltacycles thus obtained were successfully employed in the synthesis of organic compounds by the treatment with unsaturated compounds. The reaction of acetylene with nitrile proceeded catalytically and provided a convenient route to substituted pyridienes. The regioselectivities of these reactions were discussed.(2) Isonitrile was found to insert readily into a metal-carbon σ-bond and some application to the organic synthsis were described. (3) Under pressure of CO and at a high temperrature (ca. 200°C), Rh4 (CO) 12 catalyzed the arylation of ketene, isocyanate, acetylene and olefin through a C- H bond activation of aromatic compound. A. typical example is direct synthesis of styrene from benzene and ethylene. Under similar conditions, Rh4 (CO) 12 also catalyzed cross- hydrocarbonylation of acetylene and olefin affording an unsaturated lactone, RC=C (R) -CH (Et) -OCO in the presence of alcohol, and an unsaturated ketone, RCH=C (R) COEt in the presence of molecular hydrogen.