Reactivity of Alkynes with M-C Bonds generated through C-H Activation

Abstract

Transition metal-catalyzed C-H activation and functionalization with various coupling partners is a well-explored area of research. Among the various coupling partners used, alkynes occupy a prominent position on account of their varied reactivity. Due to their low steric demand and a high degree of unsaturation they effectively overlap with metal d-orbitals and form multiple bond-forming events giving rise to complex skeletons that are otherwise challenging to synthesize. This makes alkyne one of the most successful coupling partners in terms of the number of useful transformations. Remarkably, by changing the reaction conditions and transition-metals from 5d to 3d, the behaviors of alkynes also change. Despite enormous explorations with alkynes, there are still a lot more possible ways by which alkynes can be made to react with M-C bonds generated through C-H activation. Especially with the development of new high and low valent first-row metal catalysts, there is plenty of scope for this chemistry to evolve as one of the most explored areas of research in coming years. Therefore, a review on this topic is both timely and useful for synthetic chemists who are working in this area. In this review, we have highlighted the diverse reactivity of alkynes with various transition metals and their applications along with some of our thoughts on future prospects.

Expanding the Scope of Alkynes in C–H Activation: Weak Chelation-Assisted Cobalt-Catalyzed Synthesis of Indole C(4)-Acrylophenone via C–O Bond Cleavage of Propargylic Ethers

“…2 Achieving these transformations in a sustainable manner marks the need of the hour and has been the goal of researchers currently working on this topic. 3 Nowadays, chemists are focusing on exploring the reactivity of various eco-friendly transition metals such as copper, 4 iron, 5 cobalt, 6 manganese, 7 etc. Additionally, using weakly coordinating directing groups (aldehyde, ketone, ester) is another approach toward sustainable functionalization, as the modifiable nature of these directing groups after C−H bond activation makes this process synthetically more applicable.…”