Rhodium complexes asymmetrically bridged

Moreover, Complexes 118 and 119 react with mercury(II) chloride to give the IrIIi-Irl derivatives 135 and 136, resulting from oxidative addition of HgCl2 to one metal center. A related complex, [Rh2(/i-pz)2(/r-HgCl)Cl(CO)2(PPh3)2], which exhibits a mercury atom asymmetrically bridging the two rhodium centers, was previously characterized by X-ray diffraction (116). 

Asymmetric cycloisomerization of nitrogen-bridged 1,6-enynes occurs in the presence of a cationic rhodium complex coordinated with a chiral diene/phosphine tridentate ligand to give chiral 3-azabicyclo[4.1.0]heptenes with high enantioselectivity (Scheme 149). " ... 

Chiral diphosphites based on (2R,3R)-butane-2,3-diol, (2R,4R)-pentane-2,4-diol, (25, 5S)-hexane-2,5-diol, (lS -diphenylpropane-hS-diol, and tV-benzyltartarimide as chiral bridges have been used in the Rh-catalyzed asymmetric hydroformylation of styrene. Enantioselectivities up to 76%, at 50% conversion, have been obtained with stable hydridorhodium diphosphite catalysts. The solution structures of [RhH(L)(CO)2] complexes have been studied NMR and IR spectroscopic data revealed fluxional behavior. Depending on the structure of the bridge, the diphosphite adopts equatorial-equatorial or equatorial-axial coordination to the rhodium. The structure and the stability of the catalysts play a role in the asymmetric induction.218... 

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