Novel ringtransformations of pyrimidines and pyridines by intramolecular inverse electron demand Diels-Alder reactions
作者:A. E. Frissen、A. T. M. Marcelis、G. Geurtsen、D. A. de Bie、H. C. van der Plas
DOI:10.1002/recl.19871061009
日期:——
1-Dicyanopent-4-yn-1-yl)pyrimidines (1) and 2-(1,1-dicyanopent-4-yn-1-yl)nitropyridines (4) undergo intramolecularinverseelectrondemandDiels-Alder cycloaddition across the C2-C5 positions; these adducts lose hydrogen cyanide instantaneously, yielding 7,7-dicyano-6,7-dihydro-5H-1-pyrindines (3) and 1,1-dicyano-2,3-dihydronitroindenes (6), respectively. The intramolecular cyclo-additions of the pyridine derivatives