Insertion of arynes into carbon–halogen σ-bonds: regioselective acylation of aromatic rings

Direct synthesis of ortho-methylthio allyl and vinyl ethers via three component reaction of aryne, activated alkene and DMSO

A transition-metal free synthetic strategy for the direct synthesis of ortho-methylthio allyl and vinyl ethers via cascade three-component coupling of aryne, activated alkene and DMSO.

A cascade process for the synthesis of ortho-formyl allyl aryl ethers and 2H-chromen-2-ol derivatives from arynes via trapping of o-quinone methide with an activated alkene

A transition-metal free synthetic strategy for the direct synthesis of ortho-formyl substituted allyl aryl ethers and 2H-chromen-2-ol derivatives via a cascade three-component coupling of arynes, activated alkene and N,N-dimethylformamide.

Direct bromocarboxylation of arynes using allyl bromides and carbon dioxide

An unprecedented multicomponent reaction involving arynes, allyl bromides, and CO₂ has been developed to construct various allyl o-bromobenzoate scaffolds.

A facile route to 1H- and 2H-indazoles from readily accessible acyl hydrazides by exploiting a novel aryne-based molecular rearrangement

Herein we report the transformation of readily synthesised acyl hydrazides into 2-hydrazobenzophenones via a novel molecular rearrangement pathway using aryne chemistry. The developed reaction protocol is performed under relatively mild conditions and is tolerant of a wide variety of functional groups, and the 2-hydrazobenzophenone products provide access to both 1H- and 2H-indazoles from a single intermediate.

Aryne 1,2,3-Trifunctionalization with Aryl Allyl Sulfoxides

An aryne 1,2,3-trisubstitution with aryl allyl sulfoxides is accomplished, featuring an incorporation of C-S, C-O, and C-C bonds on the consecutive positions of a benzene ring. The reaction condition is mild with broad substrate scope. Preliminary mechanistic study suggests a cascade formal [2 + 2] reaction of aryne with S═O bond, an allyl S → O migration, and a Claisen rearrangement.

Copper Catalysis for Synthesizing Main-Group Organometallics Containing B, Sn or Si

A copper complex has proven to be a potent catalyst for forming a C-B bond via diborylation of arynes and alkynes, affording vic-diborylarenes and vic-diborylalkenes with high efficiency. A boryl-substituted organocopper species, which is intermediately generated in the diborylation, has been found to be captured by a tin or a carbon electrophile, leading to three-component borylstannylation or carboboration, in which C-B and C-Sn (or C) bonds are constructed simultaneously. Furthermore, reducing the Lewis acidity of the boron center with 1,8-diaminonaphthalene decisively alters the regiochemical behavior of the borylcopper species, enabling the installation of a boryl moiety to occur at an internal carbon of terminal alkynes in borylstannylation and protoboration. Copper catalysis for C-Sn and C-Si bond-forming processes via distannylation, hydrostannylation and silylstannylation, as well as silver catalysis for a C-B bond-forming reaction, is also described.

Synthesis of ortho-haloaminoarenes by aryne insertion of nitrogen-halide bonds

A rapid and general access to ortho-haloaminoarenes has been developed by aryne insertion into N-chloramine, N-bromoamine, and N-iodoamine bonds via two complementary protocols harnessing fluoride-promoted 1,2-elimination of ortho-trimethylsilyl aryltriflates. Typically, electron-deficient N-chloramines effectively react with aryne intermediates generated at elevated temperature with CsF, while less stable N-haloamines are found more efficient under milder, TBAF-mediated aryne formation at room temperature. Both protocols demonstrate a good level of regioselectivity and functional group tolerance. Efforts to elucidate the mechanism of N-X insertion are also discussed. The practical value of this transformation is highlighted by rapid synthesis of novel analogues of the antipsychotic cariprazine.

Insertion of arynes into N-halo bonds: a direct approach to o-haloaminoarenes

A new approach to access o-haloaminoarenes has been achieved by insertion of arynes into a nitrogen-halide bond (N-X). This transition-metal-free transformation displays a broad substrate scope of arynes, good compatibility with functional groups, and high regioselectivity. Representative transformations of the o-haloaminoarenes are described to highlight their utility for rapid access to diversely functionalized aminoarene derivatives.

Intermolecular C-O Addition of Carboxylic Acids to Arynes: Synthesis of o-Hydroxyaryl Ketones, Xanthones, 4-Chromanones, and Flavones

An efficient and simple route to biologically and pharmaceutically important o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones has been developed utilizing readily available carboxylic acids and commercially available o-(trimethylsilyl)aryl triflates.

Efficient multicomponent strategy to pentacyclic pyrazole-fused naphtho[1,8-fg]isoquinolines through cleavage of two carbon-carbon bonds

Multicomponent reactions of acenaphthylene-1,2-dione with diaroylmethanes and electron-rich pyrazol-5-amines have been discovered. A series of new and polyfunctionalized pentacyclic pyrazole-fused naphtho[1,8-fg]isoquinolines were regioselectively synthesized. The reactions were easy to perform simply by mixing three common reactants in AcOH. During these reaction processes, the insertion of active methylene of diaroylmethane into the sp(2)-sp(2) C-C bond of the cyclohexa-2,5-dienone ring was readily achieved and two C-C bonds were cleaved under transition-metal-free conditions.

Formation of acridones by ethylene extrusion in the reaction of arynes with β-lactams and dihydroquinolinones

N-Unsubstituted β-lactams react with a molecule of aryne by insertion into the amide bond to form a 2,3-dihydroquinolin-4-one, which subsequently reacts with another molecule of aryne to form an acridone by extrusion of a molecule of ethylene. 2,3-Dihydroquinolin-4-ones react under the same reaction conditions to afford identical results. This is the first example of ethylene extrusion in aryne chemistry.

Synthesis of 9-Substituted Xanthenes by the Condensation of Arynes with ortho-Hydroxychalcones

The reaction of o-(trimethylsilyl)aryl triflates, CsF, and o-hydroxychalcones affords a general and efficient way to prepare biologically interesting 9-substituted xanthenes. This chemistry presumably proceeds by tandem intermolecular nucleophilic attack of the phenoxide of the chalcone on the aryne and subsequent intramolecular Michael addition. The introduction of an external base, Cs(2)CO(3), has proven beneficial in this reaction.

Intermolecular C-O addition of carboxylic acids to arynes

A novel, efficient, and expedient route to biologically and pharmaceutically important o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones has been developed starting from readily available carboxylic acids and commercially available o-(trimethylsilyl)aryl triflates.

Benzyne click chemistry: synthesis of benzotriazoles from benzynes and azides

A variety of substituted benzotriazoles have been prepared by the [3 + 2] cycloaddition of azides to benzynes. The reaction scope is quite general, affording a rapid and easy entry to substituted, functionalized benzotriazoles under mild conditions.