Organocobalt complexes. Part II. Reaction of acetylenehexacarbonyldicobalt complexes, (R1C2R2)Co2(CO)6, with norbornene and its derivatives

Abstract

Tetra- and hexa-hydro-4,7-methanoinden-1-ones and the analogous indacenediones (VIII)–(X) are formed stoicheiometrically by the title reaction or catalytically from acetylenes, norbornene derivatives, and carbon monoxide in the presence of octacarbonyldicobalt. The process leads stereoselectively to ketones of theexo-series and methyl or phenyl groups derived from the appropriate monosubstituted acetylenes are always found adjacent to the carbonyl group. The ¹H n.m.r. spectra of the products are discussed and the use of an europium shift reagent together with spin decoupling is shown to allow clear distinction of the isomeric methanoindacenediones (VIII) and (IX).