Xn:Harmful;115182-22-4Relevant articles and documents
Enantiface-differentiating Enzymatic Hydrolysis of α-Substituted Cycloalkanone Enol Esters
Ohta, Hiromichi,Matsumoto, Kazutsugu,Tsutsumi, Seiji,Ihori, Tamiko
, p. 485 - 486 (1989)
2-Substituted 1-acyloxycycloalkenes have been hydrolysed with the aid of a micro-organism to afford optically active 2-substituted cycloalkanones.
Palladium-catalysed Asymmetric Allylations by a Chiral Allyl Ester; the Palladium Catalysis of (S)-Proline Allyl Ester Enamines
Hiroi, Kunio,Suya, Kyoko,Sato, Shuko
, p. 469 - 470 (1986)
The palladium-catalysed allylation of the chiral enamines (1a-d) followed by acidic hydrolysis, produced optically active 2-allylcyclohexanone (2); the catalysis of the chiral enamine (1a), derived from (S)-proline allyl ester, with tetrakis(triphenyl pho
Palladium-catalyzed stereoselective allylic alkylation of lithium enolates
Braun, Manfred,Meier, Thorsten
, p. 2968 - 2972 (2005)
The lithium enolates, generated from cyclohexanone, cyclopentanone, and 1-tetralone, react with allyl acetate 1b or carbonate 1c enantioselectively, when catalyzed by (R)- or (S)-BINAP-derived palladium complexes. The presence of lithium chloride is cruci
Formation, Alkylation, and Hydrolysis of Chiral Nonracemic N-Amino Cyclic Carbamate Hydrazones: An Approach to the Enantioselective α-Alkylation of Ketones
Huynh, Uyen,McDonald, Stacey L.,Lim, Daniel,Uddin, Md. Nasir,Wengryniuk, Sarah E.,Dey, Sumit,Coltart, Don M.
, p. 12951 - 12964 (2018/11/30)
The α-alkylation of ketones is a fundamental synthetic transformation. The development of asymmetric variants of this reaction is important given that numerous natural products, drugs, and related compounds exist as α-functionalized ketones or derivatives thereof. We previously reported our preliminary studies on the development of a new enantioselective ketone α-alkylation procedure using N-amino cyclic carbamate (ACC) auxiliaries. In comparison to other auxiliary-based methods, ACC alkylation offers a number of advantages and is both highly enantioselective and high yielding. Herein, we provide a full account of our studies on the enantioselective ACC ketone α-alkylation method.
Enantioselective oxidation by a cyclohexanone monooxygenase from the xenobiotic-degrading Polaromonas sp. strain JS666
Alexander, Anne K.,Biedermann, David,Fink, Michael J.,Mihovilovic, Marko D.,Mattes, Timothy E.
experimental part, p. 105 - 110 (2012/07/28)
A cyclohexanone monooxygenase (CHMO) from the xenobiotic-degrading Polaromonas sp. strain JS666 was heterologously expressed in Escherichia coli, and its ability to catalyze enantio- and regiodivergent oxidations of prochiral and racemic ketones was investigated. The expression system was also used to evaluate this enzyme's potential role in the oxidation of cis-1,2-dichloroethene (cDCE), a groundwater pollutant for which strain JS666 is the only known assimilator. The substrate enantiopreference and -selectivity of the strain JS666 CHMO is similar to that of other CHMO-type enzymes; of note is this enzyme's excellent stereodiscrimination of 2-substituted cyclic ketones. The expression system exhibits no activity with ethene or cDCE as substrates under the tested conditions. Phylogenetic analysis shows that sequence variability among cyclohexanone monooxygenases could be a rich source of new enzyme activities and attributes.
Induced allostery in the directed evolution of an enantioselective Baeyer-Villiger monooxygenase
Wu, Sheng,Acevedo, Juan Pablo,Reetz, Manfred T.
experimental part, p. 2775 - 2780 (2010/10/03)
The molecular basis of allosteric effects, known to be caused by an effector docking to an enzyme at a site distal from the binding pocket, has been studied recently by applying directed evolution. Here, we utilize laboratory evolution in a different way, namely to induce allostery by introducing appropriate distal mutations that cause domain movements with concomitant reshaping of the binding pocket in the absence of an effector. To test this concept, the thermostable Baeyer-Villiger monooxygenase, phenylacetone monooxygenase (PAMO), was chosen as the enzyme to be employed in asymmetric Baeyer-Villiger reactions of substrates that are not accepted by the wild type. By using the known X-ray structure of PAMO, a decision was made regarding an appropriate site at which saturation mutagenesis is most likely to generate mutants capable of inducing allostery without any effector compound being present. After screening only 400 transformants, a double mutant was discovered that catalyzes the asymmetric oxidative kinetic resolution of a set of structurally different 2-substituted cyclohexanone derivatives as well as the desymmetrization of three different 4-substituted cyclohexanones, all with high enantioselectivity. Molecular dynamics (MD) simulations and covariance maps unveiled the origin of increased substrate scope as being due to allostery. Large domain movements occur that expose and reshape the binding pocket. This type of focused library production, aimed at inducing significant allosteric effects, is a viable alternative to traditional approaches to designed directed evolution that address the binding site directly.
