29778-18-5Relevant academic research and scientific papers
Sonogashira-type cross-coupling reactions catalyzed by copper complexes of pincer N-heterocyclic carbenes
Domyati, Doaa,Latifi, Reza,Tahsini, Laleh
, p. 98 - 105 (2018)
Copper complexes of N-heterocyclic carbenes (NHC) have recently received great attention in catalysis, however, the application scope has been limited to neutral complexes bearing monodentate ligands. Herein, we report the synthesis and full characterization of a cationic Cu-pincer bis(NHC) complex with bulky tert-butyl wingtips that serves as catalyst for the coupling of aryl iodides and phenylacetylene, alongside its analogs with small alkyl substituents. Unlike other copper catalysts that require an inert atmosphere to prevent alkyne homocoupling, a competing side reaction to Sonogashira reaction, the Cu-pincer bis(NHC) complexes provide good to excellent cross-coupling yields in air. Interestingly, the reaction under argon affords substantially reduced cross-coupling, indicative of the oxygen involvement and its facilitating effect in the mechanism. In our controlled studies, the air-assisted cross-coupling reaction came to a complete stop when using a radical trap, suggesting the presence of a radical in the mechanism. Examining the reaction of Cu-pincer bis(NHC) complexes with oxygen via UV–vis spectroscopy reveals a dark green chromophore formation at ?40 °C with strong absorbance (ε > 400 M?1cm?1) at 460 nm and 500 nm, likely due to a high-valent copper-oxygen adduct.
Pd(NHC)PEPPSI-diazonium salts: An efficient blend for the decarboxylative Sonogashira cross coupling reaction
Bhojane, Jeevan Manohar,Jadhav, Vilas Gangadhar,Nagarkar, Jayashree Milind
supporting information, p. 6775 - 6780 (2017/07/17)
An efficient N-heterocyclic carbene based Pd complex is described for the de-carboxylative Sonogashira coupling reaction with diazonium salts under ligand and co-catalyst free conditions. Pd(NHC)PEPPSI not only offers an air and moisture stable pre-cataly
B(C6F5)3-Catalyzed Hydrodesulfurization Using Hydrosilanes - Metal-Free Reduction of Sulfides
Saito, Kodai,Kondo, Kazumi,Akiyama, Takahiko
, p. 3366 - 3369 (2015/07/15)
B(C6F5)3-catalyzed hydrodesulfurization of carbon-sulfur bonds was achieved using triethylsilane as the reducing agent. The corresponding products were obtained in good yields under mild reaction conditions. This protocol could be applied to the reduction of sulfides, including benzyl and alkyl sulfides and dithianes, with high chemoselectivities. (Chemical Equation Presented).
A guide to sonogashira cross-coupling reactions: The influence of substituents in aryl bromides, acetylenes, and phosphines
Schilz, Marc,Plenio, Herbert
experimental part, p. 2798 - 2807 (2012/05/05)
The conversion-time data for 168 different Pd/Cu-catalyzed Sonogashira cross-coupling reactions of five arylacetylenes (phenylacetylene; 1-ethynyl-2-ethylbenzene; 1-ethynyl-2,4,6-R3-benzene (R = Me, Et, i-Pr)) and Me3SiCCH with seven
Transition-metal-free sonogashira-type coupling of ortho-substituted aryl and alkynyl grignard reagents by using 2,2,6,6-tetramethylpiperidine-N-oxyl radical as an oxidant
Maji, Modhu Sudan,Murarka, Sandip,Studer, Armido
supporting information; experimental part, p. 3878 - 3881 (2010/11/17)
Cross coupling of aryl, alkenyl, and alkynyl magnesium compounds by using 2,2,6,6-tetramethylpiperidine-N-oxyl radical (TEMPO) as an environmentally benign organic oxidant is described. This coupling reaction can be performed without adding any transition
The effect of steric bulk in Sonogashira coupling reactions
An Der Heiden, Markus,Plenio, Herbert
, p. 972 - 974 (2007/12/31)
The rates of Sonogashira coupling reactions using [Pd-PR3] complexes depend on a combination of the steric bulk of phosphines and substrates; however, below a critical cone angle of ca. 170° the catalytic activity drops drastically. The Royal S
