Alkenylation of arylamines and N-arylacetamides with acetylene compounds in superacids

Alkenylation of Arenes and Heteroarenes with Alkynes

“…A general approach to the alkenylation of arenes with aryl acetylenes conjugated with electron-withdrawing groups, under superacidic conditions, was presented in a series of reports. − Vinyl dications 530 , generated upon protonation of the electron-withdrawing substituent and the CC triple bond of compounds 529 , react with arenes, furnishing products of arene alkenylation 531 , as E- or Z- isomers (Scheme ).…”

“…Aryl acetylene substrates 529 , having a range of different electron-withdrawing groups such as X = CO 2 Alk, − CO 2 H, CN, COMe, − COAr, C­(O)­CO 2 Et, , COCF 3 , and PO­(OEt) 2 , , may be utilized in this reaction.…”

“…Hydroarylation may be performed in different superacidic systems [HSO 3 F, TfOH, HF-SbF 5 , HSO 3 F-SbF 5 , TfOH-SbF 5 , and HX-AlX 3 (X = Cl, Br)] at temperatures ranging from −75 to 25 °C over the course of 0.25–2 h. The total yields of the reaction products range from 70% to 98%. − …”

“…Various aromatic compounds, including benzene, alkylbenzenes (mono- to tetra-substituted examples), hydroxy-, mono- and dimethoxybenzenes, halogenated arenes, arylammonium ions, N -arylacetamides, and polymethylated arenes with electron-withdrawing groups (such as 1-acetyl-2,3,5,6-tetramethylbenzene, 2,3,5,6-tetramethyl-1-fluorosulfonylbenzene, 2,3,5,6-tetramethyl-1-cyanobenzene, etc.) can be alkenylated by this method. − …”

“…Hydroarylation proceeds at −75 °C as syn -addition of proton and aryl moieties to the acetylene bond. At higher temperatures (−50 to 25 °C), the syn -adducts are converted to products of anti -addition. ,− …”