Metal-free SHN cross-coupling of pyridines with phosphine chalcogenides: polarization/deprotonation/oxidation effects of electron-deficient acetylenes. (22nd March 2021)

• Record Type: Journal Article
• Authors: Volkov, Pavel A.; Telezhkin, Anton A.; Khrapova, Kseniya O.; Ivanova, Nina I.; Albanov, Alexander I.; Gusarova, Nina K.; Trofimov, Boris A.
• Is Part Of: New journal of chemistry. Volume 45:Number 14(2021)
• Page Start: 6206
• Page End: 6219
• Publication Date: 2021-03-22
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d1nj00245g
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Terminal acylacetylenes act as trimodal auxiliaries in SHN cross-coupling of pyridines with phosphine chalcogenides. The reaction proceeds via phosphorylation of the pyridine 2 position followed by 2 → 4-migration of phosphoryl moieties. Abstract : Terminal acylacetylenes, typical electron-deficient acetylenes, drive SHN cross-coupling of pyridines with secondary phosphine chalcogenides under metal-free mild conditions (20–75 °C) to afford 4-chalcogenophosphorylpyridines in up to 70% yield. The reaction proceeds via 2, 4-migration of chalcogenophosphoryl groups in the intermediate 1-acylvinyl-2-phosphoryl dihydropyridines with simultaneous redox elimination of the vinyl ketone oligomers. These results are generalized in a concept of trimodal (polarization/deprotonation/oxidation) catalyst-like assistance of electron-deficient acetylenes in SHN reaction of the pyridinoid heterocycles with PH-nucleophiles, which comprises: (i) repolarization (umpolung) of the pyridine ring, (ii) deprotonation of secondary phosphine chalcogenides to generate phosphorus-centered anions and (iii) oxidation of the dihydro intermediates.