Synthesis, characterization and use in enantioselective hydroformylation of (BINAPO)PtCl2 (BINAPO=2-diphenylphosphino-2′-diphenylphosphinyl-1,1′-binaphthalene), the first chiral catalyst with an atropisomeric hemilabile P,O-heterodonor ligand
✍ Scribed by Serafino Gladiali; Elisabetta Alberico; Sonia Pulacchini; Làszlò Kollàr
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 116 KB
- Volume
- 143
- Category
- Article
- ISSN
- 1381-1169
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✦ Synopsis
Ž .
Ž . Ž . Platinum II complexes with the axially chiral phosphinyl phosphine S -BINAPO 1 have been prepared and their
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Ž
. behaviour in solution has been studied by P-NMR spectroscopy. Reaction of PtCl PhCN with 1 in benzene leads to the 2 2 isolation of a neutral complex, 4, which maintains the P,O-chelate coordination of the ligand even in solvents of low polarity. The hemilabile character of the ligand is apparent from the reactions with DMSO and with carbon monoxide which Ž . promote the cleavage of the chelate ring of 4 through displacement of the oxygenated arm. Insertion of tin II chloride into Ž . the Pt-Cl bond takes readily place at room temperature affording only one of the possible trichlorostannato derivatives 6 with complete selectivity. In the presence of SnCl , the platinum complex 4 originates a catalyst of remarkable 2 regioselectivity which, in the hydroformylation of styrene, is able to produce in up to 30% e.e. the branched aldehyde as the prevalent product.