Synthesis of Axially Chiral 2,2′-Bisphosphobiarenes via a Nickel-Catalyzed Asymmetric Ullmann Coupling: General Access to Privileged Chiral Ligands without Optical Resolution
Ziqing Zuo, Raphael S. Kim and Donald A. Watson*
*Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States, Email: dawatsonudel.edu
Z. Zuo, R. S. Kim, D. A. Watson, J. Am. Chem. Soc., 2021, 143, 1328-1333.
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An asymmetric homocoupling of ortho-(iodo)arylphosphine oxides and ortho-(iodo)arylphosphonates provides highly enantioenriched axially chiral bisphosphine oxides and bisphosphonates without need for optical resolution. These products are readily converted to biaryl bisphosphines. The conditions have also proven effective for asymmetric dimerization of non-phosphorus-containing aryl halides.
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Ullman reaction, biaryls, TDAE