Catalytic Asymmetric Hydrophosphinylation of 2-Vinylazaarenes to Access P-Chiral 2-Azaaryl-Ethylphosphine Oxides

Angew Chem Int Ed Engl. 2023 Apr 11;62(16):e202216605. doi: 10.1002/anie.202216605. Epub 2023 Mar 13.

Abstract

A chiral Brønsted acid-catalysed asymmetric hydrophosphinylation of 2-vinylazaarenes by secondary phosphine oxides is described. A variety of P-chiral 2-azaaryl-ethylphosphine oxides are synthesized with high yields and ees, of which both the substituents of phosphines and azaarenes can be flexibly modulated, underscoring an exceptionally broad scope of substrates. These adducts are valuable to asymmetric metal catalysis since the resultant P-chiral tertiary phosphines from the reduction of them are verified as a kind of effective C1 -symmetric chiral 1,5-hybrid P,N-ligands. Importantly, this catalysis platform enables the generic and efficient kinetic resolution of P-chiral secondary phosphine oxides. It thus provides an expedient approach to access the enantiomers of the P-chiral tertiary phosphine oxides derived from asymmetric hydrophosphinylation, further improving the utility of the method.

Keywords: Asymmetric Organocatalysis; Azaarenes; Hydrophosphinylation; Kinetic Resolution; P-Chiral Phosphines.