Binuclear and polynuclear rhodium complexes containing chiral dithiolate ligands derived from lactic acid

✍ Scribed by Z. Freixa; E. Martin; S. Gladiali; J. C. Bayón

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 127 KB
• Volume: 14
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(200001)14:1<57::aid-aoc960>3.0.co;2-l

✦ Synopsis

Two precursors of the chiral dithiolato ligands, di-[(2R)-acetylmercaptopropyl] phthalate and isophthalate, 1 and 2 respectively, were synthesized from (S)-lactic acid. Reactions of 1 and 2 with [Rh 2 (m)-OMe) 2 (cod) 2 ] (cod = 1,5-cyclo-octtadiene) yielded rhodium thiolato complexes of different nuclearities. The mixtures of complexes were analyzed by gel-permeation chromatography (GPC). The reaction with ligand 1 produced a mixture of oligomeric complexes, where the binuclear species was the main component. Higher-nuclearity complexes were the main products of the reaction with ligand 2. The rhodium complexes, in the presence of PPh 3 , were tested as catalyst precursors for the asymmetric hydroformylation of styrene. Moderate activity and regioselectivity were achieved in most cases, but no enantioselective discrimination was observed.