Electrooxidative-induced synthesis of structurally diverse seleno-dibenzocyclohepten-5-ones and seleno-spiro[5.5]trienones by selenylative carbannulation of biaryl ynones with diaryl diselenide has been developed. The switchable reactivity, intramolecular ortho-annulation or dearomative ipso-annulation, is directed by the substituent present on the ortho-aryl group of arylynone. The prominent features of this method include metal-free, external chemical oxidant-free conditions, and readily accessible substrates.Article pubs.acs.org/joc

A strategy to functionalized spiro[4.5]­trienones, by domino silver-catalyzed decarboxylative acylation or alkylation/ ipso-cyclization of N-arylpropiolamides with α-keto acids/alkyl carboxylic acids, is presented. This transformation offers a wide range of substituted 3-acyl/alkyl-spiro[4.5]­trienones in high yields with a broad substrate scope. The approach was further extended to access fused tricyclic frameworks, 6,7-dihydro-3H-pyrrolo­[2,1-j]­quinoline-3,9­(5H)-diones.

A facile oxidative dearomatization of N-(pmethoxyaryl)propiolamides has been established for the synthesis of spiro-fused 2,5-cyclohexadienone frameworks via thio(seleno)cyanative ipso-cyclization in the presence of ceric ammonium nitrate (CAN) as the oxidant. The present method, involving the formation of C−S and C−C bonds, was also extended to (pmethoxyaryl)propiolates for thiocyanative ipso-cyclization. Furthermore, the obtained chalcogeno-spirocyclohexadienones were transformed into uniquely functionalized spirocyclohexadienone derivatives.