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Upstream product

• 2008-07-3 2-benzyl-1,3-benzoxazole 
• 100-52-7 benzaldehyde 
• 273-53-0 benzoxazole 
• 501-65-5 diphenyl acetylene 

Relevant academic research and scientific papers

Rhodium/Copper Cocatalyzed Highly trans-Selective 1,2-Diheteroarylation of Alkynes with Azoles via C-H Addition/Oxidative Cross-Coupling: A Combined Experimental and Theoretical Study

Transition metal-catalyzed addition of diaryl alkynes with arylating reagents for the synthesis of tetraarylethylenes generally encounters rigorous reaction conditions and relies on the use of prefunctionalized substrates such as organic halides or surrogates and organometallic reagents. In this work, we establish a highly trans-selective 1,2-diheteroarylation of alkynes with azoles via a rhodium/copper cocatalyzed C-H addition/oxidative coupling process. Moreover, the diheteroarylation developed herein could open a door for the synthesis of heteroarene-doped tetraarylethylenes, and the photoluminescence (PL) spectra in THF-water mixtures and solid powder verify that these tetra(hetero)arylethylenes are aggregation-induced emission (AIE) active, building a new AIE molecule library. With a combination of experimental and theoretical methods, the reaction mechanism for addition/oxidative cross-coupling of internal alkynes with azoles has been investigated. Theoretical calculations reveal that the metalation/deprotonation of azole could occur with either rhodium or copper species. When azolylrhodium is formed, an alkyne could insert into the Rh-C bond. Another azolyl group could then transfer to rhodium from azolylcopper compound. The subsequent intramolecular trans-nucleophilic addition generates the second C-C bond. Meanwhile, the putative pathway for the formation of the hydroheteroarylated byproduct has also been explained by theoretical calculations.

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C-H Activation

A catalytic system comprising a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines and related azines, imidazo[1,2-a]pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic systems for analogous transformations, the present catalytic systems not only feature convenient setup using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp) but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Meanwhile, the present catalytic system proved to promote exclusively C5-selective alkenylation of imidazo[1,2-a]pyridine derivatives. Mechanistic studies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkenyl(carbamoyl)cobalt intermediate.

Regio- And Stereoselective Synthesis of Thiazole-Containing Triarylethylenes by Hydroarylation of Alkynes

Thiazole-containing π-conjugated moieties are important structural units in the development of new electronic and photochromic materials. We have developed a Pd-catalyzed syn-hydroarylation reaction of diaryl alkynes with thiazoles that provides access to thiazole-containing triarylethylenes. Pd(II) complexes derived from Pd(0) species and carboxylic acids facilitated C-H functionalization of the unsubstituted thiazole with high C5 selectivity. The catalytic system was also compatible with other azoles, such as oxazoles and a pyrazole, allowing the stereoselective syntheses of various trisubstituted olefins.

ZUR REAKTIONSWEISE DES 3-ETHOXY-1,2-DIPHENYL-CYCLOPROPENYLIUMKATIONS MIT BIFUNKTIONELLEN AROMATISCHEN AMINEN

The reaction of 3-ethoxy-1,2-diphenyl cyclopropenylium cation with bifunctional aromatic amines is described, which gives rise to benzazoles in an unexpected expansion mode of the cyclopropenone system.