Engaging the Isocyanides-Activated Alkynes Huisgen Intermediate: An Efficient Method for the Synthesis of Novel Organic Compounds

Zwitterionic (dipolar) intermediates are unstable and very reactive species which areusually generated in situ in many organic reactions and trapped during the reaction by other reactants to afford the products. There are many ways to form different zwitterionic intermediates. One of the most common methods for their generation is addition of non-protic nucleophiles to the activated alkynes. Isocyanides are especially noticeable as nucleophiles in the sense that they formed Huisgen intermediate, as one of the known zwitterionic species. Numerous significant papers have been published over the last two decades with focal theme of trapping Huisgen intermediate formed by the reaction of isocyanides with activated alkynes. In this review, different aspects of these publications based on the role of various trapping agents and then mechanisms ofactions are discussed in detail.