New developments in the synthesis of heterotopic atropisomeric diphosphines via diastereoselective aryl coupling reactions
作者:Jonathan Madec、Guillaume Michaud、Jean-Pierre Genêt、Angela Marinetti
DOI:10.1016/j.tetasy.2004.05.014
日期:2004.7
The new heterotopic atropisomeric diphosphine (R)-5,6-benzo-2,2'-bis(diphenylphosphino)-4',5',6'-trimethylbiphenyl has been prepared. The key step of this synthesis is a diastereoselective intramolecular aryl-aryl coupling reaction via oxidation of a suitable, chiral diarylcuprate. The catalytic properties of the diphosphine in ruthenium promoted hydrogenations of model substrates and in rhodium promoted 1,4-additions of boronic acids to alpha,beta-unsaturated ketones are fully comparable to those of reference ligands such as BINAP. This seems to indicate that C-2-symmetry is not a structural prerequisite for atropisomeric chiral diphosphines to obtain high enantio selectivities in 1,4-addition reactions as well as in hydrogenation reactions. (C) 2004 Elsevier Ltd. All rights reserved.