22658-92-0Relevant articles and documents
Organic-inorganic nanocrystal reductase to promote green asymmetric synthesis
Koesoema, Afifa Ayu,Matsuda, Tomoko,Tsriwong, Kotchakorn
, p. 30953 - 30960 (2020/09/11)
An acetophenone reductase from Geotrichum candidum (GcAPRD) was immobilized by the organic-inorganic nanocrystal method. The GcAPRD nanocrystal presented improved stability and recyclability compared with those of the free GcAPRD. Moreover, the GcAPRD nanocrystal reduced broad kinds of ketones with excellent enantioselectivities to produce beneficial chiral alcohols such as (S)-1-(3′,4′-dichlorophenyl)ethanol with >99% yield and >99% ee. The robust and versatile properties of the GcAPRD nanocrystal demonstrated an approach to promote green asymmetric synthesis and sustainable chemistry. This journal is
Asymmetric Enzymatic Hydration of Unactivated, Aliphatic Alkenes
Demming, Rebecca M.,Hammer, Stephan C.,Nestl, Bettina M.,Gergel, Sebastian,Fademrecht, Silvia,Pleiss, Jürgen,Hauer, Bernhard
supporting information, p. 173 - 177 (2018/12/11)
The direct enantioselective addition of water to unactivated alkenes could simplify the synthesis of chiral alcohols and solve a long-standing challenge in catalysis. Here we report that an engineered fatty acid hydratase can catalyze the asymmetric hydration of various terminal and internal alkenes. In the presence of a carboxylic acid decoy molecule for activation of the oleate hydratase from E. meningoseptica, asymmetric hydration of unactivated alkenes was achieved with up to 93 % conversion, excellent selectivity (>99 % ee, >95 % regioselectivity), and on a preparative scale.
Photostable Helical Polyfurans
Varni, Anthony J.,Fortney, Andria,Baker, Matthew A.,Worch, Joshua C.,Qiu, Yunyan,Yaron, David,Bernhard, Stefan,Noonan, Kevin J. T.,Kowalewski, Tomasz
supporting information, p. 8858 - 8867 (2019/06/07)
This report describes the design and synthesis of a new class of polyfurans bearing ester side chains. The macromolecules can be synthesized using catalyst-transfer polycondensation, providing precise control over molecular weight and molecular weight distribution. Such obtained furan ester polymers are significantly more photostable than their alkyl analogues owing to the electron-withdrawing nature of the attached subunit. Most interestingly, they spontaneously fold into a compact π-stacked helix, yielding a complex multilayer cylindrical nanoparticle with a hollow, rigid, conjugated core composed of the polyfuran backbone and a soft, insulating outer layer formed by the ester side chains. The length of polymer side chains dictates the outer diameter of such nanoparticles, which for the hexyl ester groups used in the present study is equal to ～2.3 nm. The inner cavity of the conjugated core is lined with oxygen atoms, which set its effective diameter to 0.4 nm. Furthermore, installation of bulkier, branched chiral ester side chains on the repeat unit yields structures that, upon change of solvent, can reversibly transition between an ordered chiral helical folded and disordered unfolded state.
Structural basis for a highly (S)-enantioselective reductase towards aliphatic ketones with only one carbon difference between side chain
Koesoema, Afifa Ayu,Sugiyama, Yosuke,Xu, Zichang,Standley, Daron M.,Senda, Miki,Senda, Toshiya,Matsuda, Tomoko
, p. 9543 - 9553 (2019/09/16)
Aliphatic ketones, such as 2-butanone and 3-hexanone, with only one carbon difference among side chains adjacent to the carbonyl carbon are difficult to be reduced enantioselectively. In this study, we utilized an acetophenone reductase from Geotrichum candidum NBRC 4597 (GcAPRD) to reduce challenging aliphatic ketones such as 2-butanone (methyl ethyl ketone) and 3-hexanone (ethyl propyl ketone) to their corresponding (S)-alcohols with 94% ee and > 99% ee, respectively. Through crystallographic structure determination, it was suggested that residue Trp288 limit the size of the small binding pocket. Docking simulations imply that Trp288 plays an important role to form a C-H?π interaction for proper orientation of ketones in the pro-S binding pose in order to produce (S)-alcohols. The excellent (S)-enantioselectivity is due to a non-productive pro-R binding pose, consistent with the observation that the (R)-alcohol acts as an inhibitor of (S)-alcohol oxidation.
A Straightforward Deracemization of sec-Alcohols Combining Organocatalytic Oxidation and Biocatalytic Reduction
Liardo, Elisa,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,Rebolledo, Francisca
, p. 3031 - 3035 (2018/06/27)
An efficient organocatalytic oxidation of racemic secondary alcohols, mediated by sodium hypochlorite (NaOCl) and 2-azaadamantane N-oxyl (AZADO), has been conveniently coupled with a highly stereoselective bioreduction of the intermediate ketone, catalyzed by ketoreductases, in aqueous medium. The potential of this one-pot two-step deracemization process has been proven by a large set of structurally different secondary alcohols. Reactions were carried out up to 100 mm final concentration enabling the preparation of enantiopure alcohols with very high isolated yields (up to 98 %). When the protocol was applied to the stereoisomeric rac/meso mixture of diols, these were obtained with very high enantiomeric excesses and diastereomeric ratios (95 % yield, >99 % ee, >99: 1 dr).
Biocatalytic Racemization Employing TeSADH: Substrate Scope and Organic Solvent Compatibility for Dynamic Kinetic Resolution
Pop?oński, Jaros?aw,Reiter, Tamara,Kroutil, Wolfgang
, p. 763 - 768 (2018/02/27)
Racemization in combination with a kinetic resolution is the base for a dynamic kinetic resolution (DKR). Biocatalytic racemization was successfully performed for a broad scope of sec-alcohols by employing a single alcohol dehydrogenase (ADH) variant from Thermoanaerobacter pseudoethanolicus (formerly T. ethanolicus; TeSADH W110A I86A C295A). The catalyst employed as a lyophilized whole cell preparation or cell free extract, which tolerated various non-water miscible organic solvents under micro-aqueous or two-phase conditions, whereby cyclohexane and n-hexane suited best. Various concepts for combining the enzymatic racemization with an enzymatic kinetic resolution to achieve overall a bis-enzymatic DKR were evaluated. A proof of concept showed a successful DKR with racemization in aqueous phase combined with acylation in the organic phase.
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 (2017/11/16)
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.
From a Sequential to a Concurrent Reaction in Aqueous Medium: Ruthenium-Catalyzed Allylic Alcohol Isomerization and Asymmetric Bioreduction
Ríos-Lombardía, Nicolás,Vidal, Cristian,Liardo, Elisa,Morís, Francisco,García-álvarez, Joaquín,González-Sabín, Javier
, p. 8691 - 8695 (2016/07/21)
The ruthenium-catalyzed redox isomerization of allylic alcohols was successfully coupled with the enantioselective enzymatic ketone reduction (mediated by KREDs) in a concurrent process in aqueous medium. The overall transformation, formally the asymmetric reduction of allylic alcohols, took place with excellent conversions and enantioselectivities, under mild reaction conditions, employing commercially and readily available catalytic systems, and without external coenzymes or cofactors. Optimization resulted in a multistep approach and a genuine cascade reaction where the metal catalyst and biocatalyst coexist from the beginning.
Dual stereocontrolled alkylation of aldehydes with polystyrene-supported nickel complexes derived from α-amino amides
Escorihuela, Jorge,Altava, Beln,Burguete, M. Isabel,Luis, Santiago V.
, p. 14653 - 14662 (2015/02/19)
Nickel(ii) complexes derived from α-amino amide ligands anchored to gel-type and monolithic polymers act as efficient catalysts for the enantioselective addition of dialkylzinc reagents to aldehydes. Similar to the analogous homogeneous systems, dual stereocontrol in addition products can be achieved by controlling the stoichiometry of the immobilized nickel complex. Aromatic and aliphatic aldehydes were alkylated in good yields with enantioselectivities comparable to those obtained with the homogeneous analogues. These polymer-supported catalysts offer significant advantages as no metal leaching is observed and they can be easily recovered from the reaction mixture by simple filtration and reused for subsequent experiments with consistent catalytic activity.
Regio- and stereochemistry of Na-mediated reductive cleavage of alkyl aryl ethers
Azzena, Ugo,Carraro, Massimo,Meloni, Claudia,Murgia, Irene,Pisano, Luisa,Pittalis, Mario,Luisi, Renzo,Musio, Biagia,Degennaro, Leonardo
, p. 1550 - 1554 (2015/01/09)
We have investigated the regio-and stereochemistry of the reductive dealkoxylation of alkyl aryl ethers. Chiral non-racemic secondary alcohols were converted into the corresponding m-terphenyl or 2-biphenyl ethers either via inversion of configuration under Mitsunobu reaction conditions or with retention of configuration under SNAr conditions. The successive cleavage of the aromatic C-O bond occurred in the presence of a stoichiometric amount of Na metal in dry tetrahydrofuran at rt with retention of configuration, thus highlighting that the overall inversion or retention of configuration for the whole two-step procedure is dictated by the stereochemistry of the first synthetic step.
