Cleavage of the CN Bond in Carbodiimides via Release of High Ring Strain: A New Strategy for the Selective Synthesis of 2-Aminoaryl Alkynyl Imines

Poly(ethylene glycol) Dimethyl Ethers (PEGDME): Efficient and Recyclable Solvents for Aryne-Involved Reactions

A variety of aryne reactions are demonstrated in poly(ethylene glycol) dimethyl ethers (PEGDMEs) as solvents without the need of any additive. The reactions proceed efficiently and good yields of the desired products are observed with PEGDME. Further, the advantage of being able to recycle PEG solvents is demonstrated in this work.

Rapid Synthesis of Zwitterionic Phosphonium Benzoates by a Three-Component Coupling Involving Phosphines, Arynes and CO2

A mild and easy to perform multicomponent coupling involving phosphines, arynes generated from 2-(trimethylsilyl)aryl triflates, and CO₂ allowing the transition-metal-free synthesis of zwitterionic phosphonium benzoates has been developed. The reaction proceeds via the generation of 1 : 1 zwitterionic intermediates from phosphines and arynes followed by the interception with CO₂ to deliver the carboxylates in moderate to good yields instead of the anticipated benzooxaphosphol-3(1H)-ones.

Carbodiimide-based synthesis of N-heterocycles: moving from two classical reactive sites to chemical bond breaking/forming reaction

Carbodiimides are a unique class of heterocumulene compounds that display distinctive chemical properties. The rich chemistry of carbodiimides has drawn increasing attention from chemists in recent years and has made them exceedingly useful compounds in modern organic chemistry, especially in the synthesis of N-heterocycles. This review has outlined the extensive application of carbodiimides in the synthesis of N-heterocycles from the 1980s to today. A wide range of reactions for the synthesis of various types of N-heterocyclic systems (three-, four-, five-, six-, seven-, larger-membered and fused heterocycles) have been developed on the basis of carbodiimides and their derivatives.

Synthesis of Arenesulfonyl Fluorides via Sulfuryl Fluoride Incorporation from Arynes

Transition-metal-free multicomponent reactions involving aryne precursors, secondary amines, and sulfuryl fluoride are reported herein. Zwitterionic intermediates formed from the reaction of arynes with amine nucleophiles can capture SO₂F₂ under mild conditions, offering a novel and practical protocol for the synthesis of 2-dialkyl-, 2-alkylaryl-, or 2-diarylamino-substituted arenesulfonyl fluoride derivatives in good to excellent yields.

Synthesis of o-Methyl Trifluoromethyl Sulfide Substituted Benzophenones via 1,2-Difunctionalization of Aryne by Insertion into the C-C Bond

An efficient process for the preparation of valuable o-methyl trifluoromethyl sulfide substituted benzophenones has been developed. The transition-metal-free method features insertion of aryne into a C-C σ-bond under mild reaction conditions for the first time to achieve ortho-difunctionalized arenes containing a pharmaceutically important trifluoromethylthio functional group. A wide substrate scope has been demonstrated for the developed protocol.

Synthesis of aryl triflones by insertion of arynes into C–SO2CF3 bonds

A new approach toward the synthesis of aryl triflones was achieved by the formal insertion of arynes into C–SO₂CF₃ bonds.

Employing carboxylic acids in aryne multicomponent coupling triggered by aziridines/azetidines

The transition-metal-free aryne multicomponent coupling (MCC) involving carboxylic acids initiated by aziridines/azetidines leading to the synthesis of N-aryl β/γ-amino alcohol derivatives has been developed.

Insertion/Rearrangement Reactivity of a Lutetacyclopentadiene towards N,N'-Diphenylcarbodiimide: Cooperative Effect of the Metal Center, Concentration of LiCl, and Solvent

The reactivity of lutetacyclopentadiene towards N,N'-diphenylcarbodiimide (DPC) was systematically investigated to efficiently construct three types of new N-containing fused cyclic complexes. The outcome of these reactions significantly depended on the the metal center, the concentration of LiCl, the number of equivalents of DPC, and the solvent. Thus, two unexpected reaction modes of amidinate were discovered for the first time, which were ascribed to an unusual κ(1) coordination mode of amidinate driven by a rigid seven-membered ring. These results are in striking contrast with the previously well-investigated zirconacyclopentadiene, which reacts with DPC to give azazirconacyclopentene and alkyne through β,β' CC bond cleavage. The difference in reactivity between lutetacyclopentadiene and zirconacyclopentadiene can be attributed to the highly ionic character of the LuC(sp(2) ) bonds. DFT calculations agreed well with the experimental results.

Base-Catalyzed Selective Synthesis of 2-Azabicyclo[3.2.0]hept-2-enes and Sulfonyl Vinyl-Substituted Pyrroles from 3-Aza-1,5-enynes

A base-catalyzed selective cycloisomerization of 3-aza-1,5-enynes is developed. This transformation provides a facile access to highly functionalized 2-azabicyclo[3.2.0]hept-2-enes and sulfonyl vinyl-substituted pyrroles. The chemoselectivity was controlled by the substituent pattern of the substrates.