Tetrakis(2-thienyl)allene and 1,1,3,3-tetrakis(2-thienyl)allyl cation, an electron-rich reactive tetraarylallene and a remarkably stable tetraaryl- substituted allyl cation
Tetrakis(2-thienyl)allene was synthesized as an acid-sensitive tetraarylallene by dehydration of the corresponding tetrathienylallyl alcohol with anhydrous copper(II) sulfate. This electron-rich allene forms a remarkably stable tetrathienylallyl cation by protonation, undergoes Diels- Alder reaction with tetracyanoethylene, and is capable of tetrafold lithiation and functionalization.