Transition Metal‐Catalyzed Dual C−H Activation/Annulation Reactions Involving Internal Alkynes

Recently, transition metal‐catalyzed ortho‐C−H bond activation/annulations involving two internal alkyne molecules have been extensively used to synthesize highly substituted polycyclic aromatic scaffolds. Such reactions have emerged as a powerful atom and step‐economical strategy for the assembly of multifunctional bioactive molecules. In this context, we focused on the recent achievements of dual C−H bond activation/annulations, as well as functionalization reactions involving diaryl/alkyl alkynes. Internal alkynes are an important class of organic compounds that are used as precursors for the assembly of a wide range of carbo‐, and heterocycles. Site‐selective C−H activation/annulation with two internal alkyne molecules is an interesting and intriguing topic in organic chemistry. This transformation is very important from a synthetic point of view due to the reaction performance with a high atom efficiency. Hence, in this review, we have highlighted C−H activation/annulations, as well as functionalizations involving two internal alkyne molecules.