Modular chiral ligands: the profiling of the Mandyphos and Taniaphos ligand families
作者:Felix Spindler、Christophe Malan、Matthias Lotz、Martin Kesselgruber、Ulrich Pittelkow、Andreas Rivas-Nass、Oliver Briel、Hans-Ulrich Blaser
DOI:10.1016/j.tetasy.2004.06.033
日期:2004.7
A set of 11 ferrocenyl based diphosphine ligands (eight Mandyphos and three Taniaphos) was tested in more than 150 experiments using 20 test reactions. For the assessment of new ligands, a two-pronged strategy was developed consisting of a basic and an extended profiling. The basic profiling showed that the choice of the substituents at the P atoms has a significant effect on the catalyst performance. In the extended profiling it was confirmed that the Mandyphos ligands, in particular M4 with two bis(3,5-dimethyl-4-methoxyphenyl)phosphino groups, and the Taniaphos ligands, especially the all-phenyl derivative T1, showed good to outstanding performances in the hydrogenation of selected alpha- and beta-enamides, acrylic acid derivatives, itaconates, beta-ketoesters and 1,3-diketones yielding the corresponding products with up to 99% ee and at substrate/catalyst ratios up to 25,000. (C) 2004 Elsevier Ltd. All rights reserved.