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 T1 - Synthesis of 5-arylacetylene 1,2,4-oxadiazoles and their transformations under superelectrophilic activation conditions JF - Beilstein Archives Y1 - 2021/// SN - M3 - doi:10.3762/bxiv.2021.49.v1 N2 - Acetylene derivatives of 1,2,4-oxadiazoles, 5-(2-arylethynyl)-3-aryl-1,2,4-oxadiazoles, have been obtained, for the first time, 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.  Reaction of the acetylene 1,2,4-oxadiazoles with arenes in neat triflic acid TfOH (CF3SO3H) at room temperature for 1 h result 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. Addition of TfOH to acetylene bond of these oxadiazoles gives rise quantitatively to E-/Z-vinyl triflates. Reaction cationic intermediates have been studied by DFT calculations. The reaction mechanisms have been discussed. ER -