Atropisomeric Biaryl Bisphosphine Ligands

This chapter describes atropisomeric biaryl bisphosphine ligands modified DIOP-type ligands P-chiral bisphosphane ligands other bisphosphane ligands and their applications in the enantioselective hydrogenation of olefins. 

Copyright 2007 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-31161-3 

CHEP ligand, which was successfully applied in both Rh- and Ru-catalyzed en-antioselective hydrogenation [7]. Schmid et al. reported BIPHEMP [8] and MeO-BIPHEP [9] ligands, both of which were successfully applied in many Ru-cata-lyzed hydrogenations. Achiwa also developed several atropisomeric ligands such as BIMOP [10], FUPMOP [11], and MOC-BIMOP (Fig. 26.1) [12]. 

Chan has discovered a completely atropdiasteroselective synthesis of a biaryl diphosphine based on an enantioselective intramolecular Ullmann coupling or a Fe(III)-promoted oxidative coupling. A chiral atropisomeric biaryl bisphosphine ligand 2 was synthesized through this central-to-axial chirality transfer [30]. Recently, a xylyl-biaryl bisphosphine ligand, Xyl-TetraPHEMP was introduced by Moran, and found to be effective for the Ru-catalyzed hydrogenation of aryl ketones [31]. 

---

The success of Ru-BINAP complexes in hydrogenation processes promoted the development of many related atropisomeric biaryl bisphosphine ligands. 

---