122601-54-1Relevant articles and documents
d6 and d8 Metal Carbonyl Complexes of 7,7-Dimethoxy-5,6-dimethylidenebicyclohept-2-ene. Stereoselective Hydroformylation of an Complex
Ioset, Jacques,Roulet, Raymond
, p. 236 - 247 (1985)
Reaction of 7,7-dimethoxy-5,6-dimethylidenebicyclohept-2-ene (2) with various metal carbonyls and their derivatives gave the η2-M(CO)4 (M=Fe (17), Ru (18), η4-M(CO)3 (M= Fe (19x, 19n), Ru (20n), and η2-M(CO)5 and η6-M(CO)3 (M=Cr, Mo, W) complexes.The trigonal bipyramidal η2-M(CO)4 complexes present an exceptional C3v symmetry at the metal with the C,C-double bond in an axial position.In all the η2-complexes, this double bond is stereospecifically coordinated by its exo-face.The exo- vs endo-η4-Fe(CO)3 configuration was established by chemical correlation (hydrolysis, hydrogenation) with the corresponding complexes (24x, 24n) of 7,7-dimethoxy-2,3-dimethylidenebicycloheptane (5).The relative rates of hydrolysis (AcOH/H2O 2:1, 50 deg C) of ligands 2 and 5 and of complexes 19x, 19n, 24x, and 24n to the corresponding ketones showed an acceleration effect only when the metal is coordinated to the exo-face.This was attributed to an F-strain effect on the leaving group of the substrate.Compound 17 was further metallated by giving the bimetallic isomers 21xn and 21xx.The endocyclic C,C-double bond of the latter can be stereospecifically hydroformylated (1 atm CO, AcOH/H2O, 25 deg C) giving 29x (49percent).Hydroformylation of 17 gave the corresponding uncoordinated aldehydes 30x/30n in better yields (76percent) but with lower selectivity (3:1).These are the first examples of hydroformilation of an isolated complex.
