AUTHOR=Kokuev Alexandr O. , Sukhorukov Alexey Yu. 

TITLE=Michael addition of P-nucleophiles to azoalkenes provides simple access to phosphine oxides bearing an alkylhydrazone moiety

JOURNAL=Frontiers in Chemistry

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2023.1177680

DOI=10.3389/fchem.2023.1177680

ISSN=2296-2646

ABSTRACT=<p>β-Hydrazonophosphine oxides are precursors of useful organophosphorus compounds, including phosphorylated <italic>N</italic>-heterocycles, α-aminophosphonates, and vinylphosphonates. In this work, a general transition metal-free synthesis of β-hydrazonophosphine oxides was developed. The method relies on the Michael addition of phosphine oxides R<sub>2</sub>P(O)H to reactive azoalkenes (1,2-diaza-1,3-butadienes), which are generated <italic>in situ</italic> from α-halohydrazones and Hunig’s base. The reaction stereoselectively leads to <italic>Z</italic>-isomers of β-hydrazonophosphine oxides that are stabilized by intramolecular hydrogen bonding. The conversion of the products thus obtained into potential chelating ligands was showcased.</p>