Transition-metal-catalyzed Tandem Electrophilic Cyclization Reaction Of Multiple-alkynyl Compounds

Compared with traditional methods, cascade reactions which were applied inorganic synthesis have shown considerable superiority. For example, from the aspectof environmental protection and atom economy, cascade reaction can effectivelyreduce synthetic operations and avoid purification of the intermediates. In this manner,transition-metal-catalyzed tandem electrophilic cyclization reaction is one of the mostimportant strategies for the construction of complex organic compounds, which aregenerally difficult to obtain by traditional synthetic methods. Due to the electron-richπ-conjugated systems in its molecular structure, carbon-carbon triple bonds have beenwidely recognized in tandem electrophilic cyclization reactions for a long time. Thisarticle mainly focused on the silver-catalyzed tandem electrophilic cyclizationreaction of acyclic diynols or tridynols with halogenated cations (X+), thus efficientlydeliver several kinds of natural product-like small molecules with novel cyclicstructures.In the first chapter, a brief introduction of transition-metal-catalyzed cyclizationreaction is described. We report the development of Au-catalyzed, Ag-catalyzed andPt-catalyzed near year.In the second chapter, a silver triflate-catalyzed electrophilic cyclization reactionof acyclic1,6-diynols with NXS (X=I, Br) under mild conditions is reported. Byoperating this transformation, three reactive functional groups, such as a carbonylgroup, an alkyne group, and a halogen, could be selectively installed at the C1, C2,and C3positions to obtain the naphthalene and quinoline products, respectively. Theobtained densely trisubstituted products could be further transformed into morecomplex aromatic products, simply by manipulating the alkynyl moiety and the othertwo functional groups as organic synthons.In the third chapter, the platinum(II)-catalyzed chemo-and regio-selective1,5-acyl migration reaction is described. This cascade cycloisomerization protocol produced a wide variety of funcitionized benzofulvenes diketones in good to excellentyields with exclusively (Z)-configuration exocyclic double bond of the final products.The high efficiency and good functional group compatibility demonstrates its greatpotential for the construction of important and complex benzofulvenes ring systemswith high diversity and complexity.