Construction of Heterocycles by the Strategic Use of Alkyne π-Activation in Catalyzed Cascade Reactions

This review highlights the synthesis of heterocycles via cascade reactions that involve the activation of an alkyne using carbophilic Lewis acids. Primarily guided by the type of reactivity evolving from the alkyne activation, such key steps are categorized as the addition of simple heteroatom nucleophiles, intramolecular carboalkoxylations, addition of carbonyl nucleophiles, rearrangement of propargylic esters, and enyne cycloisomerizations. Additionally, the functionalization of existing heterocycles is discussed.