350490-16-3Relevant academic research and scientific papers
Enantioselective aziridination using copper complexes of biaryl Schiff bases
Gillespie, Kevin M.,Sanders, Christopher J.,O'Shaughnessy, Paul,Westmoreland, Ian,Thickitt, Christopher P.,Scott, Peter
, p. 3450 - 3458 (2002)
Racemic 2,2′-diamino-6,6′-dimethylbiphenyl is resolved using simulated moving bed chromatography, and the absolute configuration of the enantiomers is confirmed via the X-ray crystal structure of a derivative. The diamine is condensed with a range of aldehydes to give bidentate aldimine proligands L. Molecular structures of the complexes formed between L and Cu(I) fall into two classes; bimetallic double helices ([Cu2L2]2+) and monometallic ([CuL]+). The latter are strikingly more efficient in the aziridination of alkenes than are the former in terms of rate, turnover, and enantioselection. In particular, the imine ligand formed from the diamine and 2,6-dichlorobenzaldehyde gives, in combination with Cu(I) or Cu(II), up to 99% ee in the aziridination of 6-acyl-2,2-dimethylchromene and 88-98% ee for a range of cinnamate esters. Styrenic and other alkenes are converted with lower selectivities (5-54%). The catalytic system shows a linear response in product ee to catalyst ee, and the product ee does not vary significantly during the reaction. UV spectrophotometric investigations indicate that conversion of Cu(I) to Cu(II) is not essential for catalysis but that Cu(II) is probably also a competent system.
Non-Chelate-Assisted Palladium-Catalyzed Aerobic Oxidative Heck Reaction of Fluorobenzenes and Other Arenes: When Does the C?H Activation Need Help?
Albéniz, Ana C.,Villalba, Francisco
supporting information, p. 4795 - 4804 (2021/09/06)
The pyridone fragment in the ligand [2, 2’-bipyridin]-6(1H)-one (bipy-6-OH) enables the oxidative Heck reaction of simple arenes with oxygen as the sole oxidant and no redox mediator. Arenes with either electron-donating or electron-withdrawing groups can be functionalized in this way. Experimental data on the reaction with toluene as the model arene shows that the C?H activation step is turnover limiting and that the ligand structure is crucial to facilitate the reaction, which supports the involvement of the pyridone fragment in the C?H activation step. In the case of fluoroarenes, the alkenylation of mono and 1,2-difluoro benzenes requires the presence of bipy-6-OH. In contrast, this ligand is detrimental for the alkenylation of 1,3-difluoro, tri, tetra and pentafluoro benzenes which can be carried out using just [Pd(OAc)2]. This correlates with the acidity of the fluoroarenes, the most acidic undergoing easier C?H activation so other steps of the reaction such as the coordination-insertion of the olefin become kinetically important for polyfluorinated arenes. The use of just a catalytic amount of sodium molybdate as a base proved to be optimal in all these reactions. (Figure presented.).
1,2,3-Triazol-5-ylidene-palladium complex catalyzed Mizoroki-Heck and Sonogashira coupling reactions
Inomata, Sayuri,Hiroki, Hidekatsu,Terashima, Takahiro,Ogata, Kenichi,Fukuzawa, Shin-Ichi
experimental part, p. 7263 - 7267 (2011/10/08)
The bis-1,4-dimesityl-1,2,3-triazol-5-ylidene-palladium complex (1a) successfully catalyzes the Mizoroki-Heck and Sonogashira coupling reactions with aryl bromides to give the corresponding alkenes and alkynes, respectively, in good to excellent yields. In the Mizoroki-Heck reaction, electron-rich, electron-poor, and functionalized aryl bromides and alkenes are tolerated, while the substrates are limited to electron-poor aryl halides in the Sonogashira coupling reaction. The palladium complex also catalyzes cross-coupling reactions with aryl chlorides to give higher yields of products than does the bis-IMes-Pd complex analogue (2), under specific conditions.
Synthesis and characterization of recyclable and recoverable MMT-clay exchanged ammonium tagged carbapalladacycle catalyst for Mizoroki-Heck and Sonogashira reactions in ionic liquid media
Singh, Vasundhara,Ratti, Rajni,Kaur, Sukhbir
scheme or table, p. 13 - 19 (2011/03/17)
An efficient synthesis of an ammonium tagged carbapalladacycle 5, in modest yield, has been achieved. Further, the clay-nanocomposite 6 was prepared by ion exchange of 5 into clay interlayers as a new organic-inorganic hybrid catalytic system. The ionic t
Cinnamoyl inhibitors of tissue transglutaminase
Pardin, Christophe,Pelletier, Joelle N.,Lubell, William D.,Keillor, Jeffrey W.
, p. 5766 - 5775 (2008/12/22)
(Figure Presented) Transglutaminases (TGases) catalyze the intermolecular cross-linking of certain proteins and tissue TGases (TG2) are involved in diverse biological processes. Unregulated, high TGase activities have been implicated in several physiological disorders, but few reversible inhibitors of TG2 have been reported. Herein, we report the synthesis of a series of novel trans-cinammoyl derivatives, discovered to be potent inhibitors of guinea pig liver transglutaminase. The most effective inhibitors evaluated can be sorted into two subclasses: substituted cinnamoyl benzotriazolyl amides and the 3-(substituted cinnamoyl)pyridines, referred to more commonly as azachalcones. Kinetic evaluation of both of these subclasses revealed that they display reversible inhibition and are competitive with acyl donor TGase substrates at IC50 values as low as 18 μM. An analysis of structure - activity relationships within these series of inhibitors permitted the identification of potentially important binding interactions. Further testing of some of the most potent inhibitors demonstrated their selectivity for TG2 and their potential for further development.
Rhodium-catalyzed heck-type coupling of boronic acids with activated alkenes in an aqueous emulsion
Lautens, Mark,Mancuso, John,Grover, Harpreet
, p. 2006 - 2014 (2007/10/03)
Intermolecular couplings between arylboronic acids and activated alkenes catalyzed by a water-soluble tert-bulyl amphosrhodium complex were found to progress at room temperature and generated Heck-type products with high yields and excellent selectivity. Substitution on the alkene component encouraged the formation of products arising from a conjugate addition-protonation process. In the case of Heck product formation, it was necessary to add two equivalents of the alkene component whereby one equivalent is believed to act as a sacrificial hydride acceptor.
