20780-53-4Relevant articles and documents
Unusual solvent-effect in stereochemistry of asymmetric epoxidation using a (salen)chromium(III) complex as a catalyst
Imanishi, Hirotoshi,Katsuki, Tsutomu
, p. 251 - 254 (1997)
Epoxidation of conjugated olefins has been examined with (salen)chromium(III) complexes as catalysts. Although (salen)chromium(III) complexes were catalytically less active than the corresponding (salen)manganese(III) complexes, the reactions with the chromium complexes were found to exhibit interesting solvent-dependent stereochemistry.
Asymmetric epoxidation of styrene by novel chiral ruthenium(II) Schiff base complexes, synthesis and characterization
Kureshy,Khan,Abdi,Bhatt
, p. 1693 - 1701 (1993)
Synthesis of some novel Chiral Ru(II) Schiff base complexes of the type [Rul(PPh3)(H2O)2] 1-6 where L = Chiral Schiff bases derived from salicylaldehyde and L-amino acids namely, L-alanine, L-valine, L-Serine, L-Arginine,
Confinement of CuII-phthalocyanine in a bioinspired hybrid nanoparticle-assembled structure yields selective and stable epoxidation catalysts
Manna, Joydeb,Amali, Arlin Jose,Rana, Rohit Kumar
, p. 8453 - 8457 (2014)
Herein, we demonstrate that a bioinspired assembly of silica nanoparticles with polyamines as structure-directing agents similar to that known for the biosilicification of diatoms can pave the way for the efficient encapsulation of sulfonated copper-phthalocyanine in a hybrid microcapsule structure, in which the organic component provides a capable environment for its catalytic activity in epoxidation reactions and the nanoassembled structure imparts stability.
Unmasking the Hidden Carbonyl Group Using Gold(I) Catalysts and Alcohol Dehydrogenases: Design of a Thermodynamically-Driven Cascade toward Optically Active Halohydrins
Escot, Lorena,González-Granda, Sergio,Gotor-Fernández, Vicente,Lavandera, Iván
, p. 2552 - 2560 (2022/02/16)
A concurrent cascade combining the use of a gold(I) N-heterocyclic carbene (NHC) and an alcohol dehydrogenase (ADH) is disclosed for the synthesis of highly valuable enantiopure halohydrins in an aqueous medium and under mild reaction conditions. The meth
Structural and Biochemical Studies Enlighten the Unspecific Peroxygenase from Hypoxylon sp. EC38 as an Efficient Oxidative Biocatalyst
Ebner, Katharina,Glieder, Anton,Kroutil, Wolfgang,Mattevi, Andrea,Rinnofner, Claudia,Rotilio, Laura,Swoboda, Alexander
, p. 11511 - 11525 (2021/09/22)
Unspecific peroxygenases (UPOs) are glycosylated fungal enzymes that can selectively oxidize C-H bonds. UPOs employ hydrogen peroxide as the oxygen donor and reductant. With such an easy-to-handle cosubstrate and without the need for a reducing agent, UPOs are emerging as convenient oxidative biocatalysts. Here, an unspecific peroxygenase from Hypoxylon sp. EC38 (HspUPO) was identified in an activity-based screen of six putative peroxygenase enzymes that were heterologously expressed in Pichia pastoris. The enzyme was found to tolerate selected organic solvents such as acetonitrile and acetone. HspUPO is a versatile catalyst performing various reactions, such as the oxidation of prim- and sec-alcohols, epoxidations, and hydroxylations. Semipreparative biotransformations were demonstrated for the nonenantioselective oxidation of racemic 1-phenylethanol rac-1b (TON = 13 000), giving the product with 88% isolated yield, and the oxidation of indole 6a to give indigo 6b (TON = 2800) with 98% isolated yield. HspUPO features a compact and rigid three-dimensional conformation that wraps around the heme and defines a funnel-shaped tunnel that leads to the heme iron from the protein surface. The tunnel extends along a distance of about 12 ? with a fairly constant diameter in its innermost segment. Its surface comprises both hydrophobic and hydrophilic groups for dealing with substrates of variable polarities. The structural investigation of several protein-ligand complexes revealed that the active site of HspUPO is accessible to molecules of varying bulkiness with minimal or no conformational changes, explaining the relatively broad substrate scope of the enzyme. With its convenient expression system, robust operational properties, relatively small size, well-defined structural features, and diverse reaction scope, HspUPO is an exploitable candidate for peroxygenase-based biocatalysis.
Enantiomer Separation of Nitriles and Epoxides by Crystallization with Chiral Organic Salts: Chirality Switching Modulated by Achiral Acids
Hirose, Takuji,Kodama, Koichi,Shimomura, Yuki
, p. 6552 - 6557 (2021/11/16)
Enantiomer separation of nitriles and epoxides by inclusion crystal formation with organic-salt type chiral hosts was achieved. The stereochemistry of the preferentially included nitrile could be switched only by changing the achiral carboxylic acid component. Crystallographic analysis of the inclusion crystals reveals that the hydrogen-bonding networks are controlled by the acidity of the phenol group of the acids, which results in chirality switching.