12 research outputs found
Synthese von Lactonen, Dioxinen und Nitrilen unter Verwendung von Bio- und Chemokatalysatoren
No full textRommelmann P. Synthese von Lactonen, Dioxinen und Nitrilen unter Verwendung von Bio- und Chemokatalysatoren. Bielefeld: Universität Bielefeld; 2018
Cyanide-Free and Broadly Applicable Enantioselective Synthetic Platform for Chiral Nitriles through a Biocatalytic Approach
No full textBetke T, Rommelmann P, Oike K, Asano Y, Gröger H. Cyanide-Free and Broadly Applicable Enantioselective Synthetic Platform for Chiral Nitriles through a Biocatalytic Approach. Angewandte Chemie (International ed. in English). 2017;46(40):12361-12366
Stereoselective synthesis of enantiomerically pure bowl-shaped hydroxytribenzotriquinacenes
No full textRommelmann P, Nachtigall B, Guntelmann T, Gröger H, Kuck D. Stereoselective synthesis of enantiomerically pure bowl-shaped hydroxytribenzotriquinacenes. ORGANIC & BIOMOLECULAR CHEMISTRY. 2018;16(31):5635-5642
Synthesis of Enantiomerically Pure N-Acyl Amino Nitriles via Catalytic Dehydration of Oximes and Application in a de Novo Synthesis of Vildagliptin
No full textRommelmann P, Betke T, Gröger H. Synthesis of Enantiomerically Pure N-Acyl Amino Nitriles via Catalytic Dehydration of Oximes and Application in a de Novo Synthesis of Vildagliptin. Organic Process Research & Development. 2017;21(10):1521-1527.An alternative route toward enantiomerically highly enriched N-acyl amino nitriles based on the Cu(OAc)(2)-catalyzed dehydration of aldoximes, which are readily available from N-acyl L- or D-alpha-amino aldehydes through condensation with hydroxylamine, has been developed. The desired products were obtained with high conversion and in enantiomeric excesses of 97-99% ee. Furthermore, this method has been applied in the synthesis of an N-chloroacetylated 2-cyanopyrrolidine, which represents a building block for the synthesis of Vildagliptin
An alternative approach towards poly-epsilon-caprolactone through a chemoenzymatic synthesis: combined hydrogenation, bio-oxidations and polymerization without the isolation of intermediates
No full textWedde S, Rommelmann P, Scherkus C, et al. An alternative approach towards poly-epsilon-caprolactone through a chemoenzymatic synthesis: combined hydrogenation, bio-oxidations and polymerization without the isolation of intermediates. GREEN CHEMISTRY. 2017;19(5):1286-1290.A novel synthetic route towards the polymer poly-epsilon-caprolactone based on a chemoenzymatic reaction sequence was developed. Initial hydrogenation of phenol to cyclohexanol gave a crude product, which was directly used without work-up for a subsequent biocatalytic double oxidation towards epsilon-caprolactone by means of an alcohol dehydrogenase and a monooxygenase. In order to overcome product inhibition effects, an in situ-product removal strategy via extraction of epsilon-caprolactone from an aqueous reaction medium with an organic solvent in the presence of a permeable polydimethylsiloxane membrane was applied. Furthermore, this in situ-product removal was combined with lipase-catalyzed polymerization in the organic phase at 25 degrees C. The obtained crude product contained a polymer fraction with a degree of polymerization comparable to commercial poly-epsilon-caprolactone
Biocatalytic Synthesis of Nitriles through Dehydration of Aldoximes: The Substrate Scope of Aldoxime Dehydratases
No full textBetke T, Higuchi J, Rommelmann P, et al. Biocatalytic Synthesis of Nitriles through Dehydration of Aldoximes: The Substrate Scope of Aldoxime Dehydratases. ChemBioChem. 2018;19(8):768-779.Nitriles belong to the product classes, which are mostly needed and produced by the chemical industry, playing a major role in various industry segments ranging from high-volume low-price sectors such as polymers to low-volume high-price sectors such as the chiral pharma drugs. A common industrial technology for nitrile production is ammonoxidation as a gas phase reaction at high temperature. A further popular approach are substitution or addition reactions with hydrogen cyanide or derivatives thereof. A major drawback, however, is the very high toxicity of cyanide. Recently, as a synthetic alternative, a novel enzymatic approach towards nitriles has been developed by means of so-called aldoxime dehydratases, which are capable to convert an aldoxime in one step via dehydration into nitriles. Since the aldoxime substrates are easily accessible, this route is of high interest for synthetic purposes. However, whenever a novel method is developed for organic synthesis, it raises the question of substrate scope as one of the key criteria to be applied as a "synthetic platform technology". Thus, the scope of this review is to give an overview about the current state of the substrate scope of this enzymatic method for synthesizing nitriles by means of aldoxime dehydratases. Even being a recently emerged enzyme class, a range of substrates have already been studied so far, comprising non-chiral and chiral aldoximes. It turned out that this enzyme class of aldoxime dehydratases shows a broad substrate tolerance and accepts aliphatic and aromatic aldoximes as well as arylaliphatic aldoximes. Furthermore, aldoximes bearing a stereogenic center are recognized as well and in particular for 2-arylpropylaldoximes high enantioselectivities are found. It is further noteworthy that the enantiopreference turned out to depend on the (E)- and (Z)-isomer. Thus, opposite enantiomers are accessible although starting from the same racemic aldehyde and the same enzyme.
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cyanid-freie und breit anwendbare enantioselektive Syntheseplattform für chirale Nitrile durch einen biokatalytischen Zugang
No full textBack Cover: Cyanide-Free and Broadly Applicable Enantioselective Synthetic Platform for Chiral Nitriles through a Biocatalytic Approach (Angew. Chem. Int. Ed. 40/2017)
No full textRücktitelbild: Cyanid-freie und breit anwendbare enantioselektive Syntheseplattform für chirale Nitrile durch einen biokatalytischen Zugang (Angew. Chem. 40/2017)
No full textCombining Stereoselective Enzyme Catalysis with Chirality-Assisted Synthesis in Tribenzotriquinacene Chemistry
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