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1996organo-selenium compounds, nonmetal heterocycles organo-selenium compounds, nonmetal heterocycles S 0137 -197A Novel Reaction of Selenobenzophenones with Tetracyanoethylene. Formation of a 2,3-Dihydroselenophene. -The reaction of selenobenzophenones (II) with tetracyanoethylene gives a novel type of cycloadducts (IV), sharply different from the results obtained with thiobenzophenones. Because of their property to oxidize when exposed to air, the selenobenzophenones are prepared in situ from phosphoranes (I) in the presence of elemental selenium. -(OKUMA, K.; MIYAZAKI, K.; OKUMURA, S.; TSUJIMOTO, Y.; KOJIMA, K.; OHTA, H.; YOKOMORI, Y.; Tetrahedron Lett. 36 (1995) 48, 8813-8816;

Ausgehend vom Nitro‐kronenether (Ia) wird durch Reduktion zu (Ib), Azokupplung zu (Ic) und Veretherung die E‐Azo‐Verbindung (II) hergestellt, die auf Grund des intraannularen Substituenten mit Alkali‐Kationen keine Komplexe zu bilden vermag.