Allene derivatives are a class of compounds containing a 1,2-cumulative diene unit.Their unique structural features result in diverse reactivity of them.Under this background,this thesis aims to the development of novel methods for the synthesis of functionalized aromatic(heterocyclic)compounds via cascade reactions of allenic ketones with other readily obtainable starting materials.It includes the following two chapters:In the first chapter,novel and efficient methods for the synthesis of functionalized aniline and phenol derivatives starting from allenic ketones and acetonitrile or 1-phenylbutane-1,3-dione through one-pot cascade processes including Michael addition,intramolecular cyclization and aromatization have been developed.These synthetic strategies showed advantages such as readily available starting materials,wide substrate scope,simple synthetic procedure,mild reaction conditions,and high efficiency.In the second chapter,a novel method for the synthesis of 8-methylenepyrazolo[5,1-a]isoindole(I)starting from 1-(2-bromophenyl)buta-2,3-dien-1-one(II)has been developed.To be specific,condensation of II with hydrazine hydrate affording 5-(2-bromophenyl)-1H-pyrazole followed by an intermolecular terminal alkyne hydroamination affords(Z)-5-(2-bromophenyl)-3-methyl-1-styryl-1H-pyrazole(III).The following palladium-catalyzed 5-exo intramolecular Heck coupling of III givese I in good efficiency.Compared with literature procedures for the preparation of pyrazolo[5,1-a]isoindole derivatives,the protocol developed in this thesis exhibit advantages such as easily obtainable starting materials,good functional group tolerance and high regio-selectivityIn summary,this thesis is mainly about the development of novel synthetic methodologies for the preparation of functionalized aniline(phenol)and pyrazolo[5,1-a]isoindole derivatives.In view of their unique advantages compared with literature procedures,these new methods are expected to find broad applications in synthetic organic chemistry and related areas. |