Pyridines undergo site selective cross-coupling with secondary phosphine chalcogenides (oxides, sulfides, and selenides) in the presence of acylphenylacetylenes under metal-free mild conditions (70-75 °C, MeCN) to afford 4-chalcogenophosphoryl pyridines in up to 71% yield. In this new type of SNHAr reaction acylacetylenes act as oxidants, being stereoselectively reduced to the corresponding olefins of the E-configuration.

Terminal acylacetylenes, typical electron-deficient acetylenes, drive SNH 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...

Quinolines react with acylacetylenes and secondary phosphine chalcogenides at 20–75 °C to afford N-acylvinyl-2­(1)-chalcogenophosphoryldihydroquinolines in good and excellent yields. Unlike the pyridine-derived similar intermediates, which eliminate E-alkenes to give aromatic chalcogenophosphorylpyridines, thereby completing SN HAr reaction, with quinolines, the reaction stops at the formation of the above phosphorylated N-acylvinyl-dihydroquinolines, thus representing a pendant SN HAr process. This reaction opens a one-pot atom-economic single-step access to pharmaceutically targeted phosphorylated functionalized dihydroquinolines and isoquinolines.

Acridine adds secondary phosphine chalcogenides HP(X)R 2 (X = O, S, Se; R = Ar, ArAlk) under catalystfree conditions at 70−75 °C (both in the presence and absence of the electron-deficient acetylenes) to give 9chalcogenophosphoryl-9,10-dihydroacridines in 61−94% yields. This contrasts with pyridines, which under similar conditions undergo an S N H Ar reaction, wherein electron-deficient acetylenes play the role of oxidants. For acridine, the S N H Ar step has been accomplished by the oxidation of the intermediate 9phosphoryl-9,10-dihydroacridines (X = O) with chloranil.

Quinolines undergo catalyst-free double CH-functionalization upon treatment with secondary phosphine oxides (70–75 °C, 20–48 h) followed by oxidation of the intermediate 2,4-bisphosphoryltetrahydroquinolines with chloranil. The yields of the target 2,4-bisphosphorylated quinolines are up to 77%. Thus, a double-SN HAr reaction sequence in the same molecule of quinoline has been realized. In the case of 2,4-bisphenylphosphoryltetrahydroquinolines, the aromatization occurs with elimination of one molecule of diphenylphosphine oxide to afford the products of monofunctionalization, 4-diphenylphosphorylquinolines, in 40–45% yields.

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