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1: J Org Chem. 2003 Mar 7;68(5):1701-7.Click here to read Links

Synthesis of a new chiral bisphospholane ligand for the Rh(I)-catalyzed enantioselective hydrogenation of isomeric beta-acylamido acrylates.

Holz J, Monsees A, Jiao H, You J, Komarov IV, Fischer C, Drauz K, Börner A.

Institut für Organische Katalyseforschung an der Universität Rostock e.V., Buchbinderstr. 5/6, 18055 Rostock, Germany. jens.holz@ifok.uni-rostock.de

The highly stereoselective synthesis of a chiral silylphospholane has been described, which can be advantageously used as a building block under base-free conditions for the construction of diphosphines related to DuPHOS. The utility of silylphospholane is shown in the synthesis of a new bisphospholane ligand 1 (MalPHOS), which is characterized by a maleic anhydride backbone. The ligand forms with Rh(I) a complex with a larger bite angle P-Rh-P than the analogue Me-DuPHOS complex. Both complexes have been tested in the asymmetric hydrogenation of unsaturated alpha- and beta-amino acid precursors of pharmaceutical relevance. In several cases, the new catalyst was superior in comparison to the Me-DuPHOS complex, in particular when (Z)-configured beta-acylamido acrylates were used as substrates.

PMID: 12608781 [PubMed]