Synthesis and thermolysis of rhodium and iridium complexes of endo-6-vinylbicyclo[3.1.0]hex-2-ene. A metal-promoted vinylcyclopropane to cyclopentene rearrangement

Abstract

The reaction of endo-6-vinylbicyclo[3.1.0] hex-2-ene with bisethylenerhodium(I) acetylacetonate gives rise to a 1 : 1 complex by displacement of ethylene in which the intergrity of the divinylcyclopropane is maintained. Unlike the parent hydrocarbon, which rearranges at room temperature to bicyclo[3.2.1] octa-2,6-diene, the derived rhodium complex is stable to 80°, and then the major product of rearrangement is the corresponding complex of bicyclo[3.3.0] octa-2,6-diene, minor amounts of the bicyclo [3.2.1] octa-2,6-diene derivative also being formed. Related studies on the hexafluoroacetylacetonatorhodium (I) and acetylacetonatoiridium (I) derivatives of endo-6-vinylbicyclo [3.1.0] hex-2-ene are reported. Possible mechanisms for the thermal transformation are discussed.