Synthesis Of Heterocycles Based On Tandem Cycloisomerization Strategy

The cyclic structures widely exist as elementary structures in various natural products,drug molecules,or bioactive molecules.Cyclization reactions of alkynes are of the utmost efficient methods for the construction of cyclic compounds,thus,they have been significant in the synthesis of the heterocyclic frameworks,in the related areas such as bioactive natural products,pharmaceutical industries,pesticides and photoelectric materials.Recently,organic chemists have developed numerious novel methodsutilizingthetransition-metal-catalyzedorelectropile-mediated cycloisomerization of alkynes.Compared with traditional C-C crosscoupling reaction,the cycloisomerization strategis are featured with the environmentally benign,simple operation,high resource utilization,atomic economy,as well as high chem-,regio-or stereoselectivity.We herein wish to study the cycloisomerization properties of several acetylenic compounds,with an aim to develop more convenient and efficient protocols to construct heterocyclic molecules bearing novel structural motifs.The main contents are as follows:The first section summaried the recent advances of the synthesis of heterocyclic compounds with the catalysis of transition-metals.The second section introduced an unusual Ir^III-catalyzed regio-and stereoselective C-H oxidation reaction of indoly-3-enamines,to chemo-and regioselectively afford?Z?-3-Arylidene-2-oxindole imides under neutral conditions.The third section reported an alkali-metal promoted chemo-and regioselective cycloisomerization reactions of?Z?-3-Alkylideneisoindolin-1-ones.The reaction conditions are mild and can be carried out in an air atmosphere,ommited the necessary for a transition-metal catalyst.The fourth section introduced an Fe?C₂O₄?₃.6H₂O-catalyzed tandem radical cycloisomerization reactions of 1,6-diyl-3-ones for the efficient preparation of divergent bromo-benzo[b]fluorenones.