Dicobalt hexacarbonyl-3-butyn-1-yl cobaloxime: synthesis X-ray crystal structure and reactions of the first combined cobaloxime–dicobalt hexacarbonyl alkyne complex

Reaction of 1-butynyl cobaloxime (1), synthesised by displacement of the corresponding tosylate with cobaloximato nucleophile, with dicobalt octacarbonyl gives the first trimetallic cobaloxime–dicobalt hexacarbonyl-alkyne complex (2). This trimetallic species is characterised by X-ray crystallography and undergoes the Pauson-Khand reaction to give cobaloxime-substituted cyclopentenones. We believe these are the first examples of Pauson-Khand reactions of alkynes which contain a carbon-to-metal sigma bond.