The Tandem Cycloismerization Reaction Of 1,5-Diyne Systems

Compared with traditional methods, tandem reactions display considerable preponderance in building natural product-like and bioactive compounds, which exhibit a great deal of advantages such as simple operation and atom economy. In this article, we focused on utilizing multi-alkynyl compounds as starting materials to construct a series of potential medical and photoelectric active molecular scaffolds.The main contents are as follows:The first section summarized the recent advances in transition-metal-catalyzed diynyl compounds cyclization reaction.The second section depicted an efficient and regioselective synthesis of (E)-2-vinyl-3-oxo-1-methyleneindenes, through platinum-catalyzed sequential 1,3-acyloxy migration/pentannulation/long-range 1, 5-hydride migration reaction of 1,5-diynyl esters under mild conditions. Mechanistic studies revealed that the migrated H atom was derived from unactivated alkyl group, and the long-range 1, 5-H shift was confirmed through related deuterium experiments.The third section reported a DDQ-mediated chemoselective oxidative cycloisomerization reaction of acyclic 1, 5-diynols with broad functional group tolerance. Diverse benzo[b]fluorenones were successfully obtained from this protocol.The starting materials could be easily prepared and no additional metal catalyst was necessary in the process.In the final section, an iodine-promoted propargyl alcohol iodination reaction for the synthesis of unsaturated carbonyl compounds was developed. The reaction proceeded under mild conditions via Meyer-Schuster rearrangement. The affiliated halogen atom in the products could be further functionalized via known Sonogashira or Suzuki coupling reactions.