Rhodium cationic complexes using macrocyclic diphosphines as chiral ligands:
摘要:
The mononuclear complexes [Rh(COD)(OCnP)]BF4 were prepared by adding 1,1'-binaphthyl-based diphosphine macrocyclic ligands (OCnP, n = 4-6) to a dichloromethane solution of [Rh(COD)(2)]BF4 (COD = 1,5-cyclooctadiene). Hydroformylation of styrene was carried out using solutions of rhodium-diphosphine catalyst prepared from [Rh(acac)(CO)(2)] and chiral macrocyclic diphosphines OCnP, n = 2, 4-6. At 30 bar of CO/H-2 (1:1) and 65 degrees C regioselectivities in 2-phenylpropanal were > 92% when all the chiral diphosphine was added in a P-P/Rh ratio of 2. The solution structure of the dominant species formed during the reaction of [Rh(acac)(CO)(2)] with (rac)-OC6P under hydroformylation conditions has been determined. (C) 1999 Elsevier Science S.A. All rights reserved.