Polymer Enzyme Conjugates as Chiral Ligands for Sharpless Dihydroxylation of Alkenes in Organic Solvents

Konieczny, Stefan; Leurs, Melanie; Tiller, Joerg C.

doi:10.1002/cbic.201402339

Cited by 29 publications

(25 citation statements)

References 50 publications

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“…The basis of the organo‐soluble osmate‐laccase conjugates is the modification of the enzyme with poly(2‐methyloxazoline) (PMOx) and the subsequent exchange of copper with osmate . As shown previously, these conjugates show excellent enantioselectivity in the dihydroxylation of styrene in chloroform.…”

Section: Resultsmentioning

confidence: 88%

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Optimization of and Mechanistic Considerations for the Enantioselective Dihydroxylation of Styrene Catalyzed by Osmate‐Laccase‐Poly(2‐Methyloxazoline) in Organic Solvents

2015

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The Sharpless dihydroxylation of styrene with the artificial metalloenzyme osmate‐laccase‐poly(2‐methyloxazoline) was investigated to find reaction conditions that allow this unique catalyst to reveal its full potential. After changing the co‐oxidizing agent to tert‐butyl hydroperoxide and optimizing the osmate/enzyme ratio, the turnover frequency and the turnover number could be increased by an order of magnitude, showing that the catalyst can compete with classical organometallic catalysts. Varying the metal in the active center showed that osmate is by far the most active catalytic center, but the reaction can also be realized with permanganate and iron(II) salts.

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Section: Resultsmentioning

confidence: 88%

“… Strategy for enzyme modification with PMOx and pyromellitic acid dianhydride and the suggested copper type 1 exchange with osmate by treatment with EDTA according to Ref. .…”

Section: Resultsmentioning

confidence: 99%

Optimization of and Mechanistic Considerations for the Enantioselective Dihydroxylation of Styrene Catalyzed by Osmate‐Laccase‐Poly(2‐Methyloxazoline) in Organic Solvents

2015

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“…Altogether, the measured selectivities of the 1:1 complexes of acylated LYS and BSA with osmate are with up to 98 % ee ( S ) comparable to that of other designed AME′s . This shows that simple acylation of readily available proteins and complexation with osmate renders those into enantioselective metalloenzymes for the dihydroxylation of styrene in organic solvents.…”

Section: Resultsmentioning

confidence: 99%

Multicore Artificial Metalloenzymes Derived from Acylated Proteins as Catalysts for the Enantioselective Dihydroxylation and Epoxidation of Styrene Derivatives

Leurs

Dorn

Wilhelm

et al. 2018

Chemistry A European J

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Artificial metalloenzymes (AME's) are an interesting class of selective catalysts, where the chiral environment of proteins is used as chiral ligand for a catalytic metal. Commonly, the active site of an enzyme is modified with a catalytically active metal. Here we present an approach, where the commercial proteins lysozyme (LYS) and bovine serum albumin (BSA) can be converted into highly active and enantioselective AME's. This is achieved by acylation of the proteins primary amino groups, which affords the metal salts in the core of the protein. A series of differently acylated LYS and BSA were reacted with K OsO (OH) , RuCl , and Ti(OMe) , respectively, and the conjugates were tested for their catalytic activity in dihydroxylation and epoxidation of styrene and its derivatives. The best suited system for dihydroxylation is fully acetylated LYS conjugated with K OsO (OH) , which converts styrene to 1,2-phenylethanediol with an enantioselectivity of 95 % ee (S). BSA fully acylated with hexanoic acid and conjugated with three moles RuCl per mole protein shows the highest ee values for the conversion of styrene to the respective epoxide with enenatioselectivities of over 80 % ee (R), a TON of more than 2500 and a yield of up to 78 % within 24 h at 40 °C. LYS has two favored selective binding sites for the metal catalyst and BSA has even three. The AME's with titanate in the active center invert the enantioselectivity of styrene epoxidation.

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“…Goal of the present study was to explore the potential of poly(2‐ethyloxazoline) (PEtOx) as matrix material for the activation of enzymes in electrospun nanofibers in organic solvents. We choose this polymer, because it was found enzyme friendly in solution, in amphiphilic polymer conetworks based on PEtOx, and even as enzyme–polymer conjugates to make the proteins organosoluble (Konieczny et al, ), reactive (Konieczny et al, ), and even applicable as ligands for organo‐metal catalysis (Konieczny et al, ; Leurs et al, ). Al‐Shehri et al () have reported that enzymes can be electrospun from an aqueous solution of commercial PEtOx ( M w = 500,000 g/mol).…”

Section: Resultsmentioning

confidence: 99%

Poly(2‐ethyloxazoline) as matrix for highly active electrospun enzymes in organic solvents

Plothe

Sittko

Lanfer

et al. 2016

Biotech & Bioengineering

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Nanofibers are advantageous carriers for biocatalysts, because they show lower diffusion limitations due to their high surface/volume ratio. Only a few samples are known where enzymes are directly spun into nanofibers, mostly because there are not many suited polymer carriers. In this study, poly(2-ethyloxazoline) (PEtOx) was explored regarding its usefulness to activate various enzymes in organic solvents by directly electrospinning them from aqueous solutions containing the polymer. It was found that the concentration of PEtOx in the spinning solution and also the swellability of the fibers play a great role in the activity of the enzymes in organic solvents. Using electrospun lipase B from Candida antarctica (CaLB) under optimized conditions revealed a higher carrier activity than the commercial Novozyme 435 with 10 times less immobilized protein. The electrospinning of PEtOx/CaLB fibers onto a stirrer is used to realize a biocatalytic stirrer for organic solvents. Biotechnol. Bioeng. 2017;114: 39-45. © 2016 Wiley Periodicals, Inc.

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Polymer Enzyme Conjugates as Chiral Ligands for Sharpless Dihydroxylation of Alkenes in Organic Solvents

Cited by 29 publications

References 50 publications

Optimization of and Mechanistic Considerations for the Enantioselective Dihydroxylation of Styrene Catalyzed by Osmate‐Laccase‐Poly(2‐Methyloxazoline) in Organic Solvents

Optimization of and Mechanistic Considerations for the Enantioselective Dihydroxylation of Styrene Catalyzed by Osmate‐Laccase‐Poly(2‐Methyloxazoline) in Organic Solvents

Multicore Artificial Metalloenzymes Derived from Acylated Proteins as Catalysts for the Enantioselective Dihydroxylation and Epoxidation of Styrene Derivatives

Poly(2‐ethyloxazoline) as matrix for highly active electrospun enzymes in organic solvents

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