Synthesis of functionalised quinolines through tandem addition/annulation reactions of beta-(2-aminophenyl)-alpha,beta-ynones

beta-(2-aminophenyl)-alpha,beta-ynones can quickly give functionalized 2,4-disubstituted quinolines through tandem nucleophic addition/annulations reactions. Acid-catalysed cyclization of beta-(2-aminophenyl)-alpha,beta-ynones can also occur. The easy entry into 4-iodo-2-substituted-quinolines prompted the development of a one pot procedure for synthesis of 2,4-disubstituted quinolines by further elaboration by means of palladium-catalysed reactions. The exposure to basic conditions of one beta-(2-malonylamidophenyl)-alpha,beta-ynone led to a fused quinolone derivative through intramolecular Michael addition /tautomerisation/transesterification cascade reactions. Fused polycyclic quinolines can be viewed as occurring through a tandem concerted Diels-Alder/annulation reactions of beta-(2-aminophenyl)-alpha,beta-ynones with enamines, azides and nitrile oxides. (C) 1999 Elsevier Science Ltd. Ail rights reserved.