36302-35-9Relevant academic research and scientific papers
Palladium-catalysed α-allylation of chiral sulfinimines derived from symmetric cyclic ketones
Li, Jiangnan,Dawood, Rafid S.,Qin, Shuanglin,Liu, Tongtong,Liu, Shuangwei,Stockman, Robert A.,Jiang, Shende,Yang, Guang
, p. 1146 - 1150 (2017)
A diastereoselective mono-allylation reaction at the α-position of symmetric cyclic ketones by using tert-butanesulfinamide as a chiral auxiliary is explored. Excellent yields and high diastereomeric ratios were achieved under palladium(0) catalysis in th
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.
First chemo-enzymatic synthesis of the (R)-Taniguchi lactone and substrate profiles of CAMO and OTEMO, two new Baeyer–Villiger monooxygenases
Rudroff, Florian,Fink, Michael J.,Pydi, Ramana,Bornscheuer, Uwe T.,Mihovilovic, Marko D.
, p. 157 - 165 (2017/01/17)
Abstract: This study investigates the substrate profile of cycloalkanone monooxygenase and 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-coenzyme A monooxygenase, two recently discovered enzymes of the Baeyer–Villiger monooxygenase family, used as whole-cell biocatalysts. Biooxidations of a diverse set of ketones were performed on analytical scale: desymmetrization of substituted prochiral cyclobutanones and cyclohexanones, regiodivergent oxidation of terpenones and bicyclic ketones, as well as kinetic resolution of racemic cycloketones. We demonstrated the applicability of the title enzymes in the enantioselective synthesis of (R)-(?)-Taniguchi lactone, a building block for the preparation of various natural product analogs such as ent-quinine. Graphical abstract: [Figure not available: see fulltext.]
Asymmetric Synthesis of Pyrrolidine-Containing Chemical Scaffolds via Tsuji–Trost Allylation of N-tert-Butanesulfinyl Imines
Dawood, Rafid S.,Georgiou, Irene,Wilkie, Ross P.,Lewis, William,Stockman, Robert A.
, p. 11153 - 11158 (2017/08/22)
A simple and efficient asymmetric synthesis of novel sp3-rich pyrrolidine chemical scaffolds over five steps starting from simple ketones is described. Key steps involve the use of tert-butanesulfinamide as a chiral auxiliary to perform an asym
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.
A facile and practical method of preparing optically active α-monosubstituted cycloalkanones by thermodynamically controlled deracemization
Kaku, Hiroto,Nakamaru, Aya,Inai, Makoto,Nishii, Takeshi,Horikawa, Mitsuyo,Tsunoda, Tetsuto
experimental part, p. 9450 - 9455 (2011/01/12)
Racemic 2-monosubstituted cycloalkanones were converted to R-isomers when TADDOLs (e.g., 1a, b) were used as host molecules in alkaline aqueous MeOH. The efficiency of this thermodynamically controlled deracemization was strongly influenced by the mixture ratio of the solvent, H2O/MeOH. Based on this finding, an improved method of preparing (R)-2-monosubstituted cycloalkanones with higher optical purity was developed. For example, (R)-2-(4-methylbenzyl)cyclohexanone (5) was obtained in 85% yield with 98% ee, when a 1:1 mixture of H2O/MeOH was used as the solvent in the presence of 1a.
Direct and enantioselective a-allylation of ketones via singly occupied molecular orbital (SOMO) catalysis
Mastracchio, Anthony,Warkentin, Alexander A.,Walji, Abbas M.,MacMillan, David W. C.
experimental part, p. 20648 - 20651 (2011/09/16)
The first enantioselective organocatalytic a-allylation of cyclic ketones has been accomplished via singly occupied molecular orbital catalysis. Geometrically constrained radical cations, forged from the one-electron oxidation of transiently generated ena
Laboratory evolution of robust and enantioselective Baeyer-Villiger monooxygenases for asymmetric catalysis
Reetz, Manfred T.,Wu, Sheng
supporting information; experimental part, p. 15424 - 15432 (2010/02/16)
The Baeyer-Villiger Monooxygenase, Phenylacetone Monooxygenase (PAMO), recently discovered by Fraaije, Janssen, and co-workers, is unusually thermostable, which makes it a promising candidate for catalyzing enantioselective Baeyer-Villiger reactions in organic chemistry. Unfortunately, however, its substrate scope is very limited, reasonable reaction rates being observed essentially only with phenylacetone and similar linear phenyl-substituted analogs. Previous protein engineering attempts to broaden the range of substrate acceptance and to control enantioselectivity have been met with limited success, including rational design and directed evolution based on saturation mutagenesis with formation of focused mutant libraries, which may have to do with complex domain movements. In the present study, a new approach to laboratory evolution is described which has led to mutants showing unusually high activity and enantioselectivity in the oxidative kinetic resolution of a variety of 2-aryl and 2-alkylcyclohexanones which are not accepted by the wild-type (WT) PAMO and of a structurally very different bicyclic ketone. The new strategy exploits bioinformatics data derived from sequence alignment of eight different Baeyer-Villiger Monooxygenases, which in conjunction with the known X-ray structure of PAMO and induced fit docking suggests potential randomization sites, different from all previous approaches to focused library generation. Sites harboring highly conserved proline in a loop of the WT are targeted. The most active and enantioselective mutants retain the high thermostability of the parent WT PAMO. The success of the "proline" hypothesis in the present system calls for further testing in future laboratory evolution studies.
ASYMMETRIC ALPHA FUNCTIONALIZATION AND ALPHA, ALPHA BISFUNCTIONALIZATION OF ALDEHYDES AND KETONES
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Page/Page column 19, (2009/12/05)
The present invention relates, generally, to asymmetric α-functionalization and to asymmetric α,α-bisfunctionalization of ketones and aldehydes and, in particular, to chiral auxiliaries suitable for use in effecting such functionalizations and to methods
