1123-85-9Relevant articles and documents
Anti-Markovnikov alkene oxidation by metal-oxo–mediated enzyme catalysis
Hammer, Stephan C.,Kubik, Grzegorz,Watkins, Ella,Huang, Shan,Minges, Hannah,Arnold, Frances H.
, p. 215 - 218 (2017)
Catalytic anti-Markovnikov oxidation of alkene feedstocks could simplify synthetic routes to many important molecules and solve a long-standing challenge in chemistry. Here we report the engineering of a cytochrome P450 enzyme by directed evolution to catalyze metal-oxo–mediated anti-Markovnikov oxidation of styrenes with high efficiency. The enzyme uses dioxygen as the terminal oxidant and achieves selectivity for anti-Markovnikov oxidation over the kinetically favored alkene epoxidation by trapping high-energy intermediates and catalyzing an oxo transfer, including an enantioselective 1,2-hydride migration. The anti-Markovnikov oxygenase can be combined with other catalysts in synthetic metabolic pathways to access a variety of challenging anti-Markovnikov functionalization reactions.
On the intermolecular interaction of N-benzylquininium chloride or quinine with some carbonyl group containing compounds
Avila, Thais C.,Reginato, Marcelo M.,Di Vitta, Cláudio,Ducati, Lucas C.,Andrade, Leandro H.,Marzorati, Liliana
, p. 2152 - 2157 (2016)
Interactions between N-benzylquininium chloride (Quibec) and some carbonyl group containing compounds were investigated using 1H NMR and theoretical calculations. Results highlight the importance of the hydrogen bonding between the Quibec C-9 h
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Matsumoto,T. et al.
, p. 3329 - 3336 (1979)
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Kano,S. et al.
, p. 796 (1979)
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Vanadium hydrogen sulfate (I): Chemoselective trimethylsilylation of alcohols and deprotection of trimethylsilyl ethers
Shirini, Farhad,Zolfigol, Mohammad Ali,Abedini, Masoumeh,Sakhaei, Ali Reza
, p. 943 - 946 (2008)
Trimethylsilylation of alcohols with hexamethyldisilazane (HMDS) catalyzed by V(HSO4)3 under mild and completely heterogeneous reaction condition is reported. The method is highly chemoselective for the protection of alcohols in the presence of phenols, amines and thiols. Also, the deprotection of trimethylsilyl ethers is performed in the presence of V(HSO 4)3 at room temperature in good to high yields.
Electronic effects in asymmetric hydroboration
Garner, Charles M.,Chiang, Shirley,Nething, Matthew,Monestel, Robert
, p. 8339 - 8342 (2002)
To determine whether electronic effects are operative in asymmetric hydroboration, a series of para-substituted 2-aryl-1-propenes were prepared and reacted with four asymmetric borane reagents. A significant correlation between the electronic nature of the para-substituent and the degree of asymmetric induction was observed only for a chloroborane-ether complex, not for any of several simple alkylboranes. A quantitative analysis of the relative reactivities is also given.
Sustainable radical reduction through catalytic hydrogen atom transfer
Gansaeuer, Andreas,Fan, Chun-An,Piestert, Frederik
, p. 6916 - 6917 (2008)
A system with coupled catalytic cycles is described that allows radical reduction by hydrogen atom abstraction from rhodium hydrides. These intermediates are generated from H2 activation by Wilkinson's catalyst. Radical generation is carried out by titanocene-catalyzed electron transfer to epoxides. Copyright
Brown,Yoon
, p. 1549 (1968)
A versatile approach to optically active primary 2-fluoro-2-phenylalkanols through lipase-catalyzed transformations
Goj, Olav,Burchardt, Annegret,Haufe, Guenter
, p. 399 - 408 (1997)
Kinetic resolutions of (+/-)-1-acetoxy-2-fluoro-2-phenylalkanes 1 by enzymatic hydrolysis and of (+/-)-2-fluoro-2-phenylpropanol 2a by lipase-catalyzed acetylation are described for the first time.Hydrolysis of (+/-)-1 with lipase Amano PS (Pseudomonas cepacia) provided both the optically active acetates (-)-1 and the corresponding primary alcohols (-)-2 with high enantiomeric excess. (R)-enantiopreference was observed for the acetylation of (+/-)-2-fluoro-2-phenylpropanol 2a which occurred with higher enantioselectivity and faster conversion compared to the unfluorinated parent compound (+/-)-2-phenylpropanol 3.
Organocatalytic Stereoselective Addition of Aldehydes to Acylquinolinium Ions
Mengozzi, Luca,Gualandi, Andrea,Cozzi, Pier Giorgio
, p. 3200 - 3207 (2016)
A direct and simple activation of quinolines, without isolating unstable intermediates, or using isolated N,O-acetals in the presence of Lewis or Br?nsted acids, is described. The procedure is quite straightforward and allows the addition in a stereoselective manner of different aldehydes to various differently substituted quinolines. The desired products were obtained in 28–76 % yields, with dr values up to 83:17 in favor of the syn isomer, and up to 99 % ee. Studies towards the use of acetaldehyde were also performed with different catalysts and the addition was promoted affording the desired product in 62 % yield with 46 % ee. Finally, deprotection and chemical transformations of the enantioenriched adducts were performed.
Synthesis of R-(-)-2-phenylpropanal: A potentially new route towards chiral 2-phenylalkanals
Botuha, Candice,Haddad, Mansour,Larcheveque, Marc
, p. 1929 - 1931 (1998)
A facile two step synthesis of (R)-2-phenylpropanal in high enantiomeric excess is described, starting from commercial (S)-styrene oxide, involving as a key step a Dess-Martin oxidation.
Raber et al.
, p. 8137,8139,8140,8142,8145,8146 (1978)
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Eliel,Freeman
, p. 923,925 (1952)
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Deracemisation of profenol core by combining laccase/TEMPO-mediated oxidation and alcohol dehydrogenase-catalysed dynamic kinetic resolution
Díaz-Rodríguez, Alba,Ríos-Lombardía, Nicolás,Sattler, Johann H.,Lavandera, Iván,Gotor-Fernández, Vicente,Kroutil, Wolfgang,Gotor, Vicente
, p. 1443 - 1446 (2015)
A mild one-pot methodology has been developed to deracemise rac-2-phenyl-1-propanol by combining the use of non-selective laccase/TEMPO-mediated oxidation with enantioselective bioreduction of the racemic aldehyde intermediate under dynamic conditions. The process was easily scalable and stereocontrollable by selecting the suitable biocatalyst.
The development and evaluation of a conducting matrix for the electrochemical regeneration of the immobilised co-factor NAD(H) under continuous flow
Ngamsom,Hickey,Greenway,Littlechild,McCreedy,Watts,Wiles
, p. 2419 - 2424 (2010)
Through the preparation of a novel controlled pore glass-poly(pyrrole) material we have developed a conducting support that is not only suitable for the co-immobilisation of enzymes and co-factors, but also enables the facile electrochemical regeneration of the co-factor during a reaction. Employing the selective reduction of (rac)-2-phenylpropionaldehyde to (S)-phenyl-1-propanol as a model, we have demonstrated the successful co-immobilisation of the HLADH enzyme and co-factor NAD(H); with incorporation of the material into a continuous flow reactor facilitating the in situ electrochemical regeneration of NAD(H) for in excess of 100 h. Using this approach we have developed a reagent-less, atom efficient system applicable to the cost-effective, continuous biosynthesis of chiral compounds.
Alberola
, p. 3471 (1970)
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Kharasch,M.S. et al.
, p. 3229 - 3232 (1961)
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Structural Elucidation of the Mechanism of Molecular Recognition in Chiral Crystalline Sponges
Fairen-Jimenez, David,Zaworotko, Michael J.,Zhang, Shi-Yuan
, p. 17600 - 17606 (2020)
To gain insight into chiral recognition in porous materials we have prepared a family of fourth generation chiral metal–organic frameworks (MOFs) that have rigid frameworks and adaptable (flexible) pores. The previously reported parent material, [Co2(S-mandelate)2(4,4′-bipyridine)3](NO3)2, CMOM-1S, is a modular MOF; five new variants in which counterions (BF4?, CMOM-2S) or mandelate ligands are substituted (2-Cl, CMOM-11R; 3-Cl, CMOM-21R; 4-Cl, CMOM-31R; 4-CH3, CMOM-41R) and the existing CF3SO3? variant CMOM-3S are studied herein. Fine-tuning of pore size, shape, and chemistry afforded a series of distinct host–guest binding sites with variable chiral separation properties with respect to three structural isomers of phenylpropanol. Structural analysis of the resulting crystalline sponge phases revealed that host–guest interactions, guest–guest interactions, and pore adaptability collectively determine chiral discrimination.
Water/MAO acceleration of the zirconocene-catalyzed asymmetric methylalumination of α-olefins
Wipf, Peter,Ribe, Seth
, p. 1713 - 1716 (2000)
(matrix presented) The zirconocene-catalyzed enantioselective methylalumination of terminal alkenes is greatly accelerated in the presence of water. Terminal olefins that are inert under the standard conditions can be readily methylated in good yields and with good to high enantioselectivities. Furthermore, methylaluminoxane is also shown to accelerate the reaction, albeit at a lesser rate.
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Normant,J.F. et al.
, p. 3711 - 3712 (1978)
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Zirconium-catalyzed enantioselective methylalumination of monosubstituted alkenes
Kondakov, Denis Y.,Negishi, Ei-Ichi
, p. 10771 - 10772 (1995)
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Asymmetric Reduction of Prochiral Ketones by Using Self-Sufficient Heterogeneous Biocatalysts Based on NADPH-Dependent Ketoreductases
Benítez-Mateos, Ana I.,San Sebastian, Eneko,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,López-Gallego, Fernando
, p. 16843 - 16852 (2017)
The development of cell-free and self-sufficient biocatalytic systems represents an emerging approach to address more complex synthetic schemes under nonphysiological conditions. Herein, we report the development of a self-sufficient heterogeneous biocatalyst for the synthesis of chiral alcohols without the need to add an exogenous cofactor. In this work, an NADPH-dependent ketoreductase was primarily stabilized and further co-immobilized with NADPH to catalyze asymmetric reductions without the addition of an exogenous cofactor. As a result, the immobilized cofactor is accessible, and thus, it is recycled inside the porous structure without diffusing out into the bulk, as demonstrated by single-particle in operando studies. This self-sufficient heterogeneous biocatalyst was used and recycled for the asymmetric reduction of eleven carbonyl compounds in a batch reactor without the addition of exogenous NADPH to achieve the corresponding alcohols in 100 % yield and >99 % ee; this high performance was maintained over five consecutive reaction cycles. Likewise, the self-sufficient heterogeneous biocatalyst was integrated into a plug flow reactor for the continuous synthesis of one model secondary alcohol, which gave rise to a space-time yield of 97–112 g L?1 day?1; additionally, the immobilized cofactor accumulated a total turnover number of 1076 for 120 h. This is one of the few examples of the successful implementation of continuous reactions in aqueous media catalyzed by cell-free and immobilized systems that integrate both enzymes and cofactors into the solid phase.
Regiodivergent Reductive Opening of Epoxides by Catalytic Hydrogenation Promoted by a (Cyclopentadienone)iron Complex
De Vries, Johannes G.,Gandini, Tommaso,Gennari, Cesare,Jiao, Haijun,Pignataro, Luca,Stadler, Bernhard M.,Tadiello, Laura,Tin, Sergey
, p. 235 - 246 (2022/01/03)
The reductive opening of epoxides represents an attractive method for the synthesis of alcohols, but its potential application is limited by the use of stoichiometric amounts of metal hydride reducing agents (e.g., LiAlH4). For this reason, the corresponding homogeneous catalytic version with H2 is receiving increasing attention. However, investigation of this alternative has just begun, and several issues are still present, such as the use of noble metals/expensive ligands, high catalytic loading, and poor regioselectivity. Herein, we describe the use of a cheap and easy-To-handle (cyclopentadienone)iron complex (1a), previously developed by some of us, as a precatalyst for the reductive opening of epoxides with H2. While aryl epoxides smoothly reacted to afford linear alcohols, aliphatic epoxides turned out to be particularly challenging, requiring the presence of a Lewis acid cocatalyst. Remarkably, we found that it is possible to steer the regioselectivity with a careful choice of Lewis acid. A series of deuterium labeling and computational studies were run to investigate the reaction mechanism, which seems to involve more than a single pathway.
Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
Lambert, Tristan H.,Steiniger, Keri A.
, p. 8013 - 8017 (2021/10/25)
The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
