TY - JOUR A1 - Puzanov, Andrey I. A1 - Ryabukhin, Dmitry S. A1 - Zalivatskaya, Anna S. A1 - Zakusilo, Dmitriy N. A1 - Mikson, Darya S. A1 - Boyarskaya, Irina A. A1 - Vasilyev, Aleksander V. T1 - Synthesis of 5-arylacetylenyl-1,2,4-oxadiazoles and their transformations under superelectrophilic activation conditions JF - Beilstein Journal of Organic Chemistry PY - 2021/// VL - 17 SP - 2417 EP - 2424 SN - 1860-5397 DO - 10.3762/bjoc.17.158 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.17.158 KW - acetylene-oxadiazoles KW - Friedel–Crafts reaction KW - hydroarylation KW - superelectrophilic activation KW - triflic acid N2 - Acetylene derivatives of 1,2,4-oxadiazoles, i.e., 5-(2-arylethynyl)-3-aryl-1,2,4-oxadiazoles, have been obtained, for the first time reported, from 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles by their bromination at the carbon–carbon double bond followed by di-dehydrobromination with NaNH2 in liquid NH3. The reaction of the acetylenyl-1,2,4-oxadiazoles with arenes in neat triflic acid TfOH (CF3SO3H) at room temperature for 1 h resulted in the formation of E/Z-5-(2,2-diarylethenyl)-3-aryl-1,2,4-oxadiazoles as products of regioselective hydroarylation of the acetylene bond. The addition of TfOH to the acetylene bond of these oxadiazoles quantitatively resulted in E/Z-vinyl triflates. The reactions of the cationic intermediates have been studied by DFT calculations and the reaction mechanisms are discussed. ER -