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
of diheteroaryl or diarylmanganese reagents prepared by directedmanganationusingTMP2Mn·2MgCl2·4LiCl. The resulting diorganomanganese reagents can efficiently undergo an oxidative dimerization leading to the homocoupling products in good yields. Remarkably, a number of functional groups, as well as sensitive heterocycles are tolerated using this metalation–dimerization procedure.