Synthesis of Axially Chiral 2,2′-Bisphosphobiarenes via a Nickel-Catalyzed Asymmetric Ullmann Coupling: General Access to Privileged Chiral Ligands without Optical Resolution
作者:Ziqing Zuo、Raphael S. Kim、Donald A. Watson
DOI:10.1021/jacs.0c12843
日期:2021.1.27
We report an asymmetric homocoupling of ortho-(iodo)arylphosphine oxides and ortho-(iodo)arylphosphonates resulting in highly enantioenriched axially chiral bisphosphine oxides and bisphosphonates. These products are readily converted to enantioenriched biaryl bisphosphines without need for chiralauxiliaries or optical resolution. This provides a practical route for the development of previously uninvestigated
A new and convenient method for investigating the relationship between the position of the enantiodetermining sites in chiral phosphine ligands and enantioselectivity in asymmetric hydrogenation is proposed. We have also synthesized four new diphosphine ligands, some of which give high enantioselectivity in the asymmetric hydrogenation of an enamide. (C) 2004 Elsevier Ltd. All rights reserved.