AlBr3-Promoted stereoselective anti-hydroarylation of the acetylene bond in 3-arylpropynenitriles by electron-rich arenes: synthesis of 3,3-diarylpropenenitriles

Reactions of 3-arylpropynenitriles (ArC CCN) with electron-rich arenes (Ar'H, benzene and its polymethylated derivatives) under the action of aluminum bromide (AlBr3, 6 equiv) at room temperature for 0.5-2 h result in the stereoselective formation of 3,3-diarylpropenenitriles (Ar(Ar')C=CHCN) in yields of 20-64%, as products of mainly anti-hydroarylation of the acetylene bond. The obtained 3,3-diarylpropenenitriles in triflic acid CF3SO3H (TfOH) at room temperature for 1 h are cyclized into 3-arylindenones in yields of 55-70%.

Automated summary

The reaction between 3-arylpropynenitriles and electron-rich arenes in the presence of aluminum bromide leads to the stereoselective formation of 3,3-diarylpropenenitriles, followed by cyclization into 3-arylindenones with high yields under triflic acid catalysis at room temperature.