5-Thianthrenyl-5-ylium Perchlorate

Vinyl Thianthrenium Tetrafluoroborate: A Practical and Versatile Vinylating Reagent Made from Ethylene

“…We questioned whether vinyl thianthrenium salts (vinyl-TT + ) could provide a valuable solution to this task. The perchlorate salt of vinyl-TT + was published three decades ago while exploring the reactivity of thianthene radical cation (TT •+ ) with (vinyl) 4 Sn, but only milligram quantities were accessed owing to the involvement of potentially explosive perchlorate salts, and its synthetic use has never been reported. While, in comparison with other olefins, ethylene gas typically requires high pressure and an autoclave for cycloaddition reactions, , we sought to capitalize on the high reactivity of the highly electrophilic thianthrenium dication species generated by treatment of thianthrene- S -oxide ( 2 ) with activating reagents such as Tf 2 O (Figure A).…”