2901-75-9Relevant articles and documents
Membrane Aerated Hydrogenation: Enzymatic and Chemical Homogeneous Catalysis
Greiner, Lasse,Müller, Daniela H.,Van Den Ban, Eyke C. D.,W?ltinger, Jens,Wandrey, Christian,Liese, Andreas
, p. 679 - 683 (2003)
Among the most successful systems for homogeneous catalysis, hydrogenation catalysts capable of activating molecular hydrogen, take outstanding roles in research laboratories and in industry. To open up the field of continuous catalytic hydrogenations a novel membrane reactor concept was developed and successfully applied for hydrogenations with dihydrogen both for chemical and for enzymatic catalysis. The hydrogenase I of the archaeon Pyrococcus furiosus was utilized for the continuous hydrogenation of NADP+ to NADPH with recycling of the enzyme by means of ultrafiltration. The well known PyrPhos-Rh system was used for the enantioselective synthesis of an amino acid derivative by hydrogenation.
San Filippo et al.
, p. 586 (1976)
The η5-(σ-P,π-arene) chelating H-MOP ligand in an optically and catalytically active rhodium(I) complex
Soleilhavoup, Michele,Viau, Lydie,Commenges, Gerard,Lepetit, Christine,Chauvin, Remi
, p. 207 - 212 (2003)
(R)-methylbinapium, a Hayashi-type phosphonium-MOP ligand, reacts with [Rh(cod)2][BF4] in ethanol to afford the chiral mixed bis(monophosphane)rhodium(I) complex [Rh(η5-H-MOP)(MePh2P)][BF4]. The constitutional and geometrical features of this complex have been determined by exhaustive 1H, 11B, 13C, 31P and 103Rh 1-D, 2-D and NOE NMR spectroscopy and optical rotation measurements. The chelating η5-(γ-phosphanyldiene) ligand character of H-MOP in this complex is an extension to Rh1 of similar coordination modes studied by Pregosin in the coordination sphere of RuII. The process of its formation relies on an enantiospecific reductive cleavage of a P+-C bond, which is also reminiscent of Pregosin's P-C bond cleavages in the ruthenium series. The complex is a catalytic precursor for the hydrogenation of (Z)-αacetamidocinnamic acid. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Kinetic study of homogeneous alkene hydrogenation by model discrimination
Greiner, Lasse,Ternbach, Michel Brik
, p. 1392 - 1396 (2004)
Model discrimination is one of the methods of choice to obtain a valid kinetic description of a catalytic reaction with minimal experimental effort. It allows fast judgement of catalyst behavior and its suitability for process development. Using dynamic experiments and modeling, the kinetics of a homogeneous hydrogenation with cationic rhodium-PyrPhos {[Rh(PyrPhos)(COD)] BF4} were investigated. A set of three batch experiments allowed the discrimination between 6 models. Qualitative and quantitative descriptions of the kinetic behavior could be derived. Most importantly, evidence for catalyst deactivation was gained.
Hydrogenation of α-acetamidocinnamic acid with polystyrene-supported rhodium catalysts
Bhaduri, Sumit,Lahiri, Goutam Kumar,Munshi, Pradip
, p. 151 - 155 (2000)
Divinylbenzene cross-linked chloromethylated polystyrene has been functionalised with cinchonine, ephedrine, 3S,4S-N-benzylpyrrolidinediol and four achiral amines. The resins have been used as supports for anchoring [Rh(CO)2Cl2]-. The polymer-supported complex has been tested as a catalyst precursor for the hydrogenation of α-acetamidocinnamic acid. Highest rate and modest enantioselectivity are obtained with cinchonine functionalized polymer-supported complex. This complex also undergoes reversible decarbonylation.
Takaishi et al.
, p. 5400,5402 (1976)
Minisci-Type Alkylation of N-Heteroarenes by N-(Acyloxy)phthalimide Esters Mediated by a Hantzsch Ester and Blue LED Light
Kyne, Sara Helen,Li, Jiacheng,Siang Tan, Suan,Wai Hong Chan, Philip
supporting information, (2022/01/11)
A synthetic method that enables the Hantzsch ester-mediated Minisci-type C2-alkylation of quinolines, isoquinolines and pyridines by N-(acyloxy)phthalimide esters (NHPI) under blue LED (light emitting diode) light (456 nm) is described. Achieved under mild reaction conditions at room temperature, the metal-free synthetic protocol was shown to be applicable to primary, secondary and tertiary NHPIs to give the alkylated N-heterocyclic products in yields of 21–99%. On introducing a chiral phosphoric acid, an asymmetric version of the reaction was also realised and provided product enantiomeric excess (ee) values of 53–99%. The reaction mechanism was delineated to involve excitation of an electron-donor acceptor (EDA) complex, formed from weak electrostatic interactions between the Hantzsch ester and NHPI, which generates the posited radical species of the redox active ester that undergoes addition to the N-heterocycle.
The Enantioselective Dakin-West Reaction
Wende, Raffael C.,Seitz, Alexander,Niedek, Dominik,Schuler, S?ren M. M.,Hofmann, Christine,Becker, Jonathan,Schreiner, Peter R.
supporting information, p. 2719 - 2723 (2016/02/27)
Here we report the development of the first enantioselective Dakin-West reaction, yielding α-acetamido methylketones with up to 58 % ee with good yields. Two of the obtained products were recrystallized once to achieve up to 84 % ee. The employed methylimidazole-containing oligopeptides catalyze both the acetylation of the azlactone intermediate and the terminal enantioselective decarboxylative protonation. We propose a dispersion-controlled reaction path that determines the asymmetric reprotonation of the intermediate enolate after the decarboxylation.
Potassium Thioacids Mediated Selective Amide and Peptide Constructions Enabled by Visible Light Photoredox Catalysis
Liu, Hongxin,Zhao, Liyun,Yuan, Yunfei,Xu, Zhifang,Chen, Kai,Qiu, Shengxiang,Tan, Haibo
, p. 1732 - 1736 (2016/03/15)
A remarkable visible-light-promoted photoredox catalytic methodology involved with amines and eco-friendly potassium thioacids for amide formation was uncovered. This approach can mimic the natural coenzyme acetyl-CoA to selectively acylate amines without affecting other functional groups such as alcohols, phenols, esters, among others. The developed strategy may hold great potential for a comprehensive display of biologically interesting peptide synthesis and amino acid modification through a diacyl disulfide intermediate.
