Cyclization of n-alkylazinium cations with bisnucleophiles. 4. Regio- and stereospecificity of the reactions of β-diketones with quinoxalinium salts and their aza and benzo analogs

The reactions of substituted quinoxalinium, benzo[g]- and benzo[f]quinoxalinium, and pyrido[2,3-b]pyrazinium salts with anions of -dicarbonyl compounds give furo[2,3-b]-annelated systems with strictly determined regio- and stereoorientations.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1543–1548, November, 1981.