| Metal-catalyzed cycloisomerization reactions of 1,n-enynes have appeared as conceptually and chemically highly attractive processes as they contribute to the highly demanded search for atom economy and allow the discovery of new reactions. Since the pioneering studies with palladium by the research group of Barry Trost in the mid-1980s, several other metals have been identified as excellent catalysts for the rearrangement of enyne skeletons. Moreover, the behavior of 1,n-enynes may be influenced by other functional groups such as alcohols, aldehydes, ethers, alkenes, or alkynes, thus enhancing the molecular complexity of the synthesized products. Apart from the intrinsic rearrangements of 1,n-enynes, several tandem reactions incorporating intramolecular trapping agents or intermolecular partners have been discovered.Recent years, we also have some studies on copper and bismuth catalyzed domino cycloisomerization reactions of 1,n-enynes for synthesis of polycyclic aromatic hydrocarbons (PAHs), as shown in the following 3 parts:Partâ… :We developed a novel intermolecular condensation reaction of 1,3,5-triarylenynols catalysed by copper, which involved dimerization fragmentation and [4+2] cycloaddition-dehydrogenation. This reaction is a straightforward method for the synthesis of highly conjugated aromatic 1H-cyclopenta[b]naphthalenes. These products are extremely useful in material chemistry.Part 2:We developed a straightforward method for the synthesis of multisubstituted fluorene with (Z)-2-en-4-yn acetates and ethynylbenzene catalyzed by BiBr3 via domino reaction, which involved intermolecular, intramolecular electrophilic addition and cycloisomerization aromatization. Variation of substituted groups was proven possible and this reaction can proceed smoothly in moderate to good yields.Part 3:A new and efficient synthesis of substituted indene has been achieved via Copper (â… )-catalyzed domino three-components coupling and cyclization reaction inmoderate to good yield...
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