Hydrido−Rhodium(I) and −Iridium(I) Complex Promoted Ring-Opening Isomerization of Unsymmetrically Substituted Methylenecyclopropanes into 1,3-Dienes. Structures of Intermediates and Reaction Pathways

2-Phenyl-1-methylenecyclopropane and 2,2-diphenyl-1-methylenecyclopropane react with MH(CO)(PPh 3 ) 3 (M = Rh, Ir) to produce 1,3-dienes or the intermediate Rh and Ir complexes having a 3-butenyl ligand, depending on the conditions. The structures and chemical properties of the obtained complexes suggest plausible pathways for the ring-opening isomerization of the methylenecyclopropanes to the corresponding dienes.