Rhodium cationic complexes using dithioethers as chiral ligands. Application in styrene hydroformylation
Orejón, A., Masdeu-Bultó, A.M., Echarri, R., Diéguez, M., Forniés-Cámer, J., Claver, C. and Cardin, C. (1998) Rhodium cationic complexes using dithioethers as chiral ligands. Application in styrene hydroformylation. Journal of Organometallic Chemistry , 559 (1-2). pp. 23-29. ISSN 0022-328X
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To link to this item DOI: 10.1016/S0022-328X(97)00692-X
Addition of the dithioethers (−)-DIOSR2 (R=Me, iPr) (2,3-O-isopropylidene-1,4-dimethyl (and diisopropyl) thioether-L-threitol) to a dichloromethane solution of [Rh(COD)2]ClO4 (COD=1,5-cyclooctadiene) yielded the mononuclear complexes [Rh(COD)(DIOSR2)]ClO4. X-ray diffraction methods showed that the [Rh(COD)(DIOSiPr2)]ClO4 complex had an square-planar coordination geometry at the rhodium atom with the iPr groups in anti position. Cyclooctadiene complexes react with carbon monoxide to form dinuclear tetracarbonylated complexes [(CO)2Rh(μ-DIOSR2)2(CO)2](ClO4)2. [Rh(COD)(DIOSR2)]ClO4 are active catalyst precursors in styrene hydroformylation at 30 atm and 65°C which give conversions of up to 99% with a regioselectivity in 2-phenylpropanal as high as 74%. In all cases enantioselectivities are low.