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Upstream product

• 763-12-2 2-methyl-3,5-hexadiyn-2-ol 
• 696-62-8 para-iodoanisole 
• 768-60-5 4-methoxyphenylacetylen 
• 3989-14-8 (4-methoxyphenylethynyl)trimethylsilane 
• 100-66-3 methoxybenzene 
• 84384-30-5 4-(4-methoxyphenyl)-2-methyl-3-butyn-2-ol 
• 115-19-5 2-methyl-but-3-yn-2-ol 
• 33675-41-1 1-bromo-2-(4-methoxyphenyl)acetylene 
• 2063-19-6 4-bromo-2-methylbut-3-yn-2-ol 

Downstream Products

• 22779-13-1 2-((4-methoxyphenyl)buta-1,3-diyn-1-yl)pyridine 
• 128810-17-3 1-(4-methoxyphenyl)-4-[2,5-bis(trifluoromethyl)phenyl]-1,3-butadiyne 
• 7642-31-1 1-(4-methoxyphenyl)-1,3-butadiyne 
• 1246638-01-6 1-methoxy-4-(5-methylhexa-3,4-dien-1-ynyl)benzene 
• 1342819-72-0 5-(4-methoxybenzyl)-2,2-dimethylfuran-3(2H)-one 
• 1342819-93-5 5-(4-methoxybenzoyl)-2,2-dimethylfuran-3(2H)-one 
• 42545-43-7 2-(4-methoxyphenyl)thiophene 
• 1510810-63-5 4,4'-(7-hydroxy-1-((4-hydroxyphenyl)ethynyl)-9H-fluorene-9,9-diyl)diphenol 

Relevant academic research and scientific papers

Cyclobutene vs 1,3-Diene Formation in the Gold-Catalyzed Reaction of Alkynes with Alkenes: The Complete Mechanistic Picture

The intermolecular gold(I)-catalyzed reaction between arylalkynes and alkenes leads to cyclobutenes by a [2 + 2] cycloaddition, which takes place stepwise, first by formation of cyclopropyl gold(I) carbenes, followed by a ring expansion. However, 1,3-butadienes are also formed in the case of ortho-substituted arylalkynes by a metathesis-type process. The corresponding reaction of alkenes with aryl-1,3-butadiynes, ethynylogous to arylalkynes, leads exclusively to cyclobutenes. A comprehensive mechanism for the gold(I)-catalyzed reaction of alkynes with alkenes is proposed on the basis of density functional theory calculations, which shows that the two pathways leading to cyclobutenes or dienes are very close in energy. The key intermediates are cyclopropyl gold(I) carbenes, which have been independently generated by retro-Buchner reaction from stereodefined 1a,7b-dihydro-1H-cyclopropa[a]naphthalenes.

In Situ Synthesis of CuN4/Mesoporous N-Doped Carbon for Selective Oxidative Crosscoupling of Terminal Alkynes under Mild Conditions

The 1,3-conjugated diynes are an important class of chemical intermediates, and the selective crosscoupling of terminal alkynes is an efficient chemical process for manufacturing asymmetrical 1,3-conjugated diynes. However, it often occurs in homogenous conditions and costs a lot for reaction treatment. Herein, a copper catalyzed strategy is used to synthesize highly ordered mesoporous nitrogen-doped carbon material (OMNC), and the copper species is in situ transformed into the copper single-atom site with four nitrogen coordination (CuN4). These features make the CuN4/OMNC catalyst efficient for selective oxidative crosscoupling of terminal alkynes, and a wide range of asymmetrical and symmetrical 1,3-diynes (26 examples) under mild conditions (40?°C) and low substrates ratio (1.3). Density functional theory (DFT) calculations reveal that the aryl–alkyl crosscoupling has the lowest energy barrier on the CuN4 site, which can explain the high selectivity. In addition, the catalyst can be separated and reused by simply centrifugation or filtration. This work can open a facile avenue for constructing single-atom loaded mesoporous materials to bridge homogeneous and heterogeneous catalysis.

Tuning of cross-Glaser products mediated by substrate-catalyst polymeric backbone interactions

Tuning of cross-Glaser products using different polymeric backbones supported by copper oxide nano-catalysts has been demonstrated by tweaking the substrate-catalyst interactions under greener conditions. Further, highly reactive magnetically separable and recyclable catalyst with scalability is demonstrated.

One-pot synthesis of unsymmetrical 1,3-butadiyne derivatives and their application in the synthesis of unsymmetrical 2,5-diarylthiophenes

A one-pot protocol was developed for the synthesis of unsymmetrical 1,3-butadiynes. The procedure is based on two sequential reactions: deprotection of R–C≡C–C≡C– C(Me)2OH derivatives in a retro-Favorskii reaction to furnish a terminal 1,3-butadiyne compound, which reacted with aryl iod-ides in a Sonogashira-type cross-coupling reaction catalyzed by Pd(PPh3)4 and CuI, using TBAOH as activator and toluene as solvent under reflux for 10 min. We also studied in situ thiocycli-zation of 1,3-butadiynes, leading to unsymmetrical 2,5-diaryl-thiophenes. The principal features of this method are operational simplicity, good substrate scope, very fast reaction, and high yields.

Facilitating Gold Redox Catalysis with Electrochemistry: An Efficient Chemical-Oxidant-Free Approach

Due to the high oxidation potential between AuI and AuIII, gold redox catalysis requires at least stoichiometric amounts of a strong oxidant. We herein report the first example of an electrochemical approach in promoting gold-catalyzed oxidative coupling of terminal alkynes. Oxidation of AuI to AuIII was successfully achieved through anode oxidation, which enabled facile access to either symmetrical or unsymmetrical conjugated diynes through homo-coupling or cross-coupling. This report extends the reaction scope of this transformation to substrates that are not compatible with strong chemical oxidants and potentiates the versatility of gold redox chemistry through the utilization of electrochemical oxidative conditions.

Copper Nanoparticles on Ordered Mesoporous Carbon Nitride Support: a Superior Catalyst for Homo- and Cross-Coupling of Terminal Alkynes under Base-Free Conditions

A novel ordered mesoporous carbon nitride (OMCN) was synthesized as a functionalized support with 2,4,6-trichloro-1,3,5-triazine and benzidine as starting materials in the presence of SBA-15 as a template. Copper nanoparticles were then loaded on the C–N material to achieve a novel nanocomposite catalyst (Cu NPs-OMCN). The nanocomposite was utilized as a highly efficient catalyst for homo- and cross-coupling of terminal alkynes under base-free conditions in ethanol, and various symmetrical and unsymmetrical 1,3-diynes were obtained with good to excellent yields. Moreover, based on this reaction, a one-pot approach to synthesize 2,5-disubstituted thiophenes and furans from terminal alkynes were developed. Furthermore, the heterogeneous catalyst could be recovered and reused conveniently for several times with satisfactory yields.

Gold-Catalyzed Oxidative Coupling of Alkynes toward the Synthesis of Cyclic Conjugated Diynes

Gold-catalyzed oxidative coupling of alkynes was developed as an efficient approach for the synthesis of challenging cyclic conjugated diynes (CCD). Compared with the classic copper-promoted oxidative coupling reaction of alkynes, this gold-catalyzed process exhibited a faster reaction rate due to rapid reductive elimination from the Au(III) intermediate. This unique reactivity thus allowed a challenging diyne macrocyclization to take place with high efficiency. Condition screening revealed an [(n-Bu)4N]+[Cl-Au-Cl]? salt as the optimal pre-catalyst. Macrocycles with ring size between 13 and 28 atoms were prepared in moderate to good yields, which highlighted the broad substrate scope of this new strategy. Furthermore, the synthetic utilities of the CCDs for copper-free click chemistry have been demonstrated, showcasing the potential application of this strategy in biological systems. Macrocycles are important structural moieties in medicinal and biological research, and efficient methods for macrocyclization are always in high demand. With the unique conformation having six carbon atoms in a linear geometry, the cyclic conjugated diynes (CCD) present greater synthetic challenges and have been much less explored. Therefore, application of these unique macrocycles in biological studies is largely unexplored. Here, we describe the discovery of gold-catalyzed Glaser-Hay type oxidative coupling of terminal alkynes to achieve CCD under diluted conditions with broad substrate scope and great functional group compatibility. Taking advantage of the 14-member cyclic diyne, a copper-free click chemistry was achieved, which provided an effective alternative strategy for the traditional cyclooctyne-based azide-alkyne cycloaddition, suggesting a promising future for this method in tackling challenging problems in related biological and medicinal research. Gold-catalyzed oxidative coupling of alkynes was developed as an efficient approach for the synthesis of challenging cyclic conjugated diyne. Compared with copper-promoted oxidative coupling, this protocol allowed macrocyclization under dilute conditions with good overall reactivity and high functional group tolerance. The success in achieving copper-free click chemistry on cyclic conjugated diyne highlights its potential application in biological and medicinal research.

Transition-Metal-Free Synthesis of Borylated Thiophenes via Formal Thioboration

A simple, regiocontrolled, and transition-metal-free approach to access exclusively 3-borylated thiophene derivatives is reported. The commercially available B-chlorocatecholborane reagent (ClBcat) acts as a carbophilic Lewis acid to activate the alkyne i

Glaser-Hay hetero-coupling in a bimetallic regime: A Ni(II)/Ag(i) assisted base, ligand and additive free route to selective unsymmetrical 1,3-diynes

A Ni(OAc)2/Ag(OTf) catalysed coupling of aryl alkynes and propargylic alcohol/ether/ester gave the corresponding unsymmetrical 1,3-diynes in good to excellent yields. The reaction does not require bases, ligands or additives and shows excellent hetero-selectivity, thereby addressing the current challenges in the field of coupling of two different terminal alkynes.

Copper Catalysis for Selective Heterocoupling of Terminal Alkynes

A Cu-catalyzed selective aerobic heterocoupling of terminal alkynes is disclosed, which enables the synthesis of a broad range of unsymmetrical 1,3-diynes in good to excellent yields. The results disprove the long-held belief that homocouplings are exclusively favored in the Glaser-Hay reaction.