260435-36-7Relevant academic research and scientific papers
Highly Efficient Heck Reactions of Aryl Bromides with n-Butyl Acrylate Mediated by a Palladium/Phosphine-Imidazolium Salt System
Yang, Chuluo,Lee, Hon Man,Nolan, Steven P.
, p. 1511 - 1514 (2001)
matrix presented A new phosphine-imidazolium salt, L·HBr (1, L = (1-ethylenediphenylphosphino-3-(mesityl))imidazol-2-ylidene), has been prepared. A combination of 0.5 mol % of Pd(dba)2 and 0.5 mol % of L·HBr in the presence of 2 equiv of Cssub
A concise, asymmetric synthesis of methyl (1S,2R)-1-amino-2,3-dihydro- 1H-indene-2-carboxylate: A novel, constrained β-amino ester
Price, David A.
, p. 1919 - 1920 (1999)
The concise, asymmetric synthesis of methyl (1S,2R)-1-amino-2,3-dihydro- 1H-indene-2-carboxylate is reported using a novel tandem conjugate addition, intramolecular electrophilic trap to construct the indane skeleton.
Thermodynamic Understanding of an Aza-Michael Reaction Enables Five-Step Synthesis of the Potent Integrin Inhibitor MK-0429
Gupta, Anya,Condakes, Matthew L.
supporting information, p. 17523 - 17527 (2021/11/18)
We describe a general strategy for the aza-Michael addition of nucleophilic heterocycles into β-substituted acrylates using potassium tert-butoxide as catalyst. Demonstrating that the reaction is under thermodynamic control underpins optimization efforts and enables rapid exploration of the substrate scope, with yields ranging from 55% to 94%. We further leverage these lessons in a significantly shortened synthesis of MK-0429, a potent pan-integrin inhibitor previously taken into human clinical trials for the treatment of prostate cancer and osteoporosis.
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.).
Enantioselective Synthesis of β-Amino Acid Derivatives Enabled by Ligand-Controlled Reversal of Hydrocupration Regiochemistry
Buchwald, Stephen L.,Guo, Sheng,Zhu, Jiaqi
supporting information, p. 20841 - 20845 (2020/09/16)
A Cu-catalyzed enantioselective hydroamination of α,β-unsaturated carbonyl compounds for the synthesis of β-amino acid derivatives was achieved through ligand-controlled reversal of the hydrocupration regioselectivity. While the hydrocupration of α,β-unsaturated carbonyl compounds to form α-cuprated species has been extensively investigated, we report herein that, in the presence of an appropriate ancillary chiral ligand, the opposite regiochemistry can be observed for cinnamic acid derivatives, leading to the delivery of the copper to the β-position. This copper can react with an electrophilic aminating reagent, 1,2-benzisoxazole, to provide enantioenriched β-amino acid derivatives, which are important building blocks for the synthesis of natural products and bioactive small molecules.
A simple catalytic system based on PdCl2(CH3CN) 2 in water for cross-coupling reactions using diazonium salts
El Bakouri, Ouissam,Fernández, Martí,Brun, Sandra,Pla-Quintana, Anna,Roglans, Anna
, p. 9761 - 9765 (2013/10/22)
Aryl-heteroaryl and heteroaryl-heteroaryl compounds are obtained through the Suzuki-Miyaura cross-coupling reactions between diazonium salts and potassium trifluoroborates using PdCl2(CH3CN)2 as the catalyst in water and in the absence of any additive, ligand or base. In addition, the same mild catalytic system is effective for the Matsuda-Heck reaction between several monoolefins with aryldiazonium salts.
A convenient and mild chromatography-free method for the purification of the products of Wittig and Appel reactions
Byrne, Peter A.,Rajendran, Kamalraj V.,Muldoon, Jimmy,Gilheany, Declan G.
supporting information; experimental part, p. 3531 - 3537 (2012/05/20)
A mild method for the facile removal of phosphine oxide from the crude products of Wittig and Appel reactions is described. Work-up with oxalyl chloride to generate insoluble chlorophosphonium salt (CPS) yields phosphorus-free products for a wide variety of these reactions. The CPS product can be further converted into phosphine.
Heck-Matsuda reactions catalyzed by a hydroxyalkyl-functionalized NHC and palladium acetate
Penafiel, Itziar,Pastor, Isidro M.,Yus, Miguel
supporting information; experimental part, p. 3151 - 3156 (2012/07/03)
The functionalized NHC obtained from salt 2 is a good ligand for palladium in the Heck-Matsuda reaction of arenediazonium salts and different alkenes. The reaction is performed with low catalyst loading (0.5-1 mol-% of Pd) and in the absence of a base for acrylates. The protocol is also useful for the preparation of cinnamide derivatives. Compound U-77863 has been prepared successfully in good isolated yield. Cyclohexene was found to be an appropriate substrate for the reaction, giving the corresponding 1-arylcyclohexene as a single regioisomer under the studied reaction conditions. The optimal parameters of the reaction were studied by employing a design of experiments approach. Thus, the use of a small set of reactions allows the trends of the different factors to be studied. This study revealed that the best catalytic system is formed by combination of Pd(OAc)2 and salt 2 in a 1:2 ratio. This catalytic system produces better results without the use of a base. Copyright
Palladium-catalyzed C-C bond formation of arylhydrazines with olefins via carbon-nitrogen bond cleavage
Zhu, Ming-Kui,Zhao, Jun-Feng,Loh, Teck-Peng
supporting information; experimental part, p. 6308 - 6311 (2012/01/06)
The unactivated carbon-nitrogen bond of various aryl hydrazines was cleaved under very mild conditions by Pd(0) with the assistance of Pd(II). The in situ generated aryl palladium complex readily takes part in the C-C bond formation with olefins. This study offered a new mode of C-Pd bond formation, which will spur the development of palladium-catalyzed cross-coupling in the future.
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.
