105643-09-2Relevant articles and documents
Stereoselective and Site-Specific Allylic Alkylation of Amino Acids and Small Peptides via a Pd/Cu Dual Catalysis
Huo, Xiaohong,He, Rui,Fu, Jingke,Zhang, Jiacheng,Yang, Guoqiang,Zhang, Wanbin
, p. 9819 - 9822 (2017/08/02)
We report a stereoselective and site-specific allylic alkylation of Schiff base activated amino acids and small peptides via a Pd/Cu dual catalysis. A range of noncoded α,α-dialkyl α-amino acids were easily synthesized in high yields and with excellent enantioselectivities (up to >99% ee). Furthermore, a direct and highly stereoselective synthesis of small peptides with enantiopure α-alkyl or α,α-dialkyl α-amino acids residues incorporated at specific sites was accomplished using this dual catalyst system.
Terephthalic acid derived ligand-stabilized palladium nanocomposite catalyst for Heck coupling reaction: without surface-modified heterogeneous catalyst
Jithendra kumara,Krishnamurthy,Kumara swamy,Shashi kumar,Naik, Satish,Krishna,Naik, Nagaraj
, (2016/12/26)
A new protocol is reported for the synthesis of a heterogeneous palladium nanocomposite stabilized with a terephthalic acid-derived ligand (N,N-bis(4-hydroxy-3-methoxybenzylidene)terephthalohydrazide). This is a highly insoluble ligand in common organic solvents, except dimethylformamide and dimethylsulfoxide. The resulting palladium nanocomposite acts as an efficient catalyst precursor for Mizoroki–Heck coupling reactions conducted under various reaction conditions. The spectral data suggest that the rate, yield and recycling of the catalyst are more effective for C–C coupling reactions. Copyright
Organic synthesis via magnetic attraction: Benign and sustainable protocols using magnetic nanoferrites
Nasir Baig,Varma, Rajender S.
, p. 398 - 417 (2013/03/14)
Magnetic nano-catalysts have been prepared using simple modification of iron ferrites. The nm size range of these particles facilitates the catalysis process, as an increased surface area is available for the reaction; the easy separation of the catalysts by an external magnet and their recovery and reuse are additional beneficial attributes. Glutathione bearing nano-ferrites have been used as organocatalysts for the Paal-Knorr reaction and homocoupling of boronic acids. Nanoferrites, post-synthetically modified by ligands, were used to immobilize nanometals (Cu, Pd, Ru, etc.) which enabled the development of efficient, sustainable and green procedures for azide-alkynes-cycloaddition (AAC) reactions, C-S coupling, O-allylation of phenol, Heck-type reactions and hydration of nitriles.
Mechanistic investigations of bipyrimidine-promoted palladium-catalyzed allylic acetoxylation of olefins
Lin, Bo-Lin,Labinger, Jay A.,Bercaw, John E.
experimental part, p. 264 - 271 (2009/10/23)
Several pyridine-like ligands were found to improve Pd(OAc) 2-catalyzed allylic oxidation of allylbenzene to cinnamyl acetate by p-benzoquinone in acetic acid. The best ligand examined, bipyrimidine, was used to identify the catalyst precursor for this system, (bipyrimidine)Pd(OAc) 2, which was fully characterized. Mechanistic studies suggest the reaction takes place through disproportionation of (bipyrimidine)Pd(OAc) 2 to form a bipyrimidine-bridged dimer, which reacts with olefin to form a PdII-olefin adduct, followed by allylic C-H activation to produce (η3-allyl)PdII species. The (η3-allyl)PdII intermediate undergoes a reversible acetate attack to generate a Pd0-(allyl acetate) adduct, which subsequently reacts with p-benzoquinone to release allyl acetate and regenerate (bipyrimidine)Pd(OAc)2. No KIE is observed for the competition experiment between allylbenzene-d0 and allylbenzene-d5 (CD2=CDCD2C6H5), suggesting that allylic C-H activation is not rate-determining. Catalytic allylic acetoxylations of other terminal olefins as well as cyclohexene were also effected by (bipyrimidine)Pd(OAc)2.
Oxidation by Cobalt(III) Acetate. Part 10. Effects of Ring Substituents on the Product Distributions in the Oxidation of β-Methylstyrenes by Cobalt(III) Acetate in Acetic Acid
Morimoto, Takashi,Hirano, Masao,Echigoya, Kohki,Sato, Takafumi
, p. 1205 - 1210 (2007/10/02)
The oxidation of ring-substituted β-methylstyrenes by cobalt(III) acetate in acetic acid has been studied by product analysis and the relative rates were measured by a competition method.Electron-releasing groups (p-MeO, pMe and p-But) accelerated both the reaction rate and the formation of glycol monoacetates, while electron-withdrawing groups (p-Cl and m-Cl) not only retarded the reaction but also favoured the formation of allylic acetate instead of glycol monoacetate.The good relationship of relative rates with ?+ in the Hammett plot showed that both products were derived from the same intermediate.The reaction mechanism is discussed in connection with the stabilities of radical cations formed by a one-electron transfer from the olefins to cobalt(III) acetate.
Electron-transfer Processes: Oxidation of α- and β-Alkenylbenzenes by Peroxydisulphate in Acetic Acid
Citterio, Attilio,Arnoldi, Claudio,Giordano, Claudio,Castaldi, Grasiano
, p. 891 - 896 (2007/10/02)
Oxidation of α- and β-unsaturated alkylbenzenes by peroxydisulphate in acetic acid gives side-chain acetoxylation with formation of the corresponding glycol diacetates and compounds (10), respectively.The reaction is catalysed by transition-metal salts, among which cupric acetate gives the best results.Generally, electron-releasing substituents on the benzene ring increase the yield and improve the selectivity.The same substrates are oxidized in water under Ag+ catalysis to the corresponding aldehydes.The different behaviour in the two solvents is ascribed to the difference in reactivity between the primary oxidation products and the starting olefin, whereas the initial oxidation step is suggested to occur in both cases via an electron-transfer process from the olefin to the sulphate radical anion.
