Kokuev AO, Sukhorukov AY. Michael addition of
P-nucleophiles to azoalkenes provides simple access to phosphine oxides bearing an alkylhydrazone moiety.
Front Chem 2023;
11:1177680. [PMID:
37123875 PMCID:
PMC10133514 DOI:
10.3389/fchem.2023.1177680]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 03/27/2023] [Indexed: 05/02/2023] Open
Abstract
β-Hydrazonophosphine oxides are precursors of useful organophosphorus compounds, including phosphorylated N-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 R2P(O)H to reactive azoalkenes (1,2-diaza-1,3-butadienes), which are generated in situ from α-halohydrazones and Hunig's base. The reaction stereoselectively leads to Z-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.
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