Alkynes are amongst the most valuable functional groups in organic chemistry and widely used in chemical biology, pharmacy, and materials science. However, the preparation of alkyl-substituted alkynes still remains elusive. Here, we show a nickel-catalyzed deaminative Sonogashira coupling of alkylpyridinium salts. Key to the success of this coupling is the development of an easily accessible and bench-stable amide-type pincer ligand. This ligand allows naturally abundant alkyl amines as alkylating agents in Sonogashira reactions, and produces diverse alkynes in excellent yields under mild conditions. Salient merits of this chemistry include broad substrate scope and functional group tolerance, gram-scale synthesis, one-pot transformation, versatile late-stage derivatizations as well as the use of inexpensive pre-catalyst and readily available substrates. The high efficiency and strong practicability bode well for the widespread applications of this strategy in constructing functional molecules, materials, and fine chemicals.

The direct iminoalkynylation of unactivated olefins with terminal alkynes is achieved for the first time by nickel-catalyzed cascade iminyl-radical cyclization/Sonogashira-type coupling of γ,δ-unsaturated oxime esters under mild conditions. This transformation...

Reported herein is a new copper-catalyzed N−H/C−H sequential relay oxidative radical carboannulation of [60]fullerene with C2-functionalized free indoles for the direct construction of novel [60]fullerene-fused tetrahydrocyclopenta-[b]indoles. The transformation shows high regioselectivity and atom economy, broad substrate scope, and good functional group tolerance, providing an efficient and practical approach to access diversely substituted fullerene-fused polycyclic derivatives from simple hydrocarbons.

Herein, we report a general and practical nickel-catalyzed deaminative allenylation of amino acid derivatives with terminal alkynes. The well-designed, electron deficient, and sterically hindered amide-type NN 2 pincer ligand was crucial to the success of this transformation, enabling the coupling to occur under mild conditions with high efficiency. The remarkable features of this chemistry are its good scalability, its broad substrate scope, functional group tolerance, and the efficient modification of peptides, drugs, and natural products.

Allenes are one of the most important functional groups in organic chemistry, featuring unique physical and chemical properties. They are not only the key scaffolds widely present in natural products, pharmaceutical molecules, and advanced functional materials, but also the valuable and versatile building blocks for the construction of various complex and bioactive molecules in organic synthesis. Accordingly, benefiting from the rapid development of transition metal catalysis, numerous remarkable and efficient approaches for the synthesis of allenes from readily available chemicals have been established in the past decades. In this brief review, we focus on the recent advancements in nickel‐catalyzed synthesis of allenes. These transformations are divided into two categories according to the types of reactions and sorted further by starting materials. Moreover, a concise discussion of the limitations and potential areas of improvement in this field is also provided, which would give an inspiration for future study on allene synthesis.