A novel reaction of selenobenzophenones with tetracyanoethylene. Formation of a 2,3-dihydroselenophene

Unusual formation of a thiacyclopent‐2‐ene by the reaction of 4,4′‐dimethoxythiobenzophenone with tetracyanoethylene

“…In a previous article, we have reported an unusual reaction of selenobenzophenones with TCNE to give a novel type of cycloadducts, selenacyclopent-2-enes (4), sharply different from the above result with thiobenzophenone (Scheme 1) [5]. These results prompted us to investigate the possibility to form thiacyclopent-2-enes from thiobenzophenones.…”

1,4‐Dioxo‐1,4‐dihydronaphthalene‐2,3‐dicarbonitrile and 1,1,2,2‐Tetracyanoethene in Heterocyclization

“…The reaction of selenobenzophenones 144 with TCNE 2 exclusively affords an unusual type of adduct 145 with the structure of 2,3‐dihydroselenophene ( 145 , Scheme ) , sharply different from the reaction between thiobenzophenone 146 and 2 . In the latter case, 3,4‐dicyano‐2,5‐bis‐(diphenylmethyleneamino)thiophene ( 147 ) was obtained (Scheme ) .…”