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 rea ctions. Acid-catalysed cyclization of beta-(2-aminophenyl)-alpha,beta-ynone s can also occur. The easy entry into 4-iodo-2-substituted-quinolines promp ted the development of a one pot procedure for synthesis of 2,4-disubstitut ed quinolines by further elaboration by means of palladium-catalysed reacti ons. The exposure to basic conditions of one beta-(2-malonylamidophenyl)-al pha,beta-ynone led to a fused quinolone derivative through intramolecular M ichael addition /tautomerisation/transesterification cascade reactions. Fus ed polycyclic quinolines can be viewed as occurring through a tandem concer ted Diels-Alder/annulation reactions of beta-(2-aminophenyl)-alpha,beta-yno nes with enamines, azides and nitrile oxides. (C) 1999 Elsevier Science Ltd . Ail rights reserved.