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4. Two (Chemo)-enzymatic cascades for the production of opposite enantiomers of chiral azidoalcohols

Author

Calderini, Elia (author), Süss, Philipp (author), Hollmann, F. (author), Wardenga, Rainer (author), Schallmey, Anett (author), Calderini, Elia (author), Süss, Philipp (author), Hollmann, F. (author), Wardenga, Rainer (author), and Schallmey, Anett (author)

Abstract

Multi-step cascade reactions have gained increasing attention in the biocatalysis field in recent years. In particular, multi-enzymatic cascades can achieve high molecular complexity without workup of reaction intermediates thanks to the enzymes’ intrinsic selectivity; and where enzymes fall short, organo-or metal catalysts can further expand the range of possible synthetic routes. Here, we present two enantiocomplementary (chemo)-enzymatic cascades composed of either a styrene monooxygenase (StyAB) or the Shi epoxidation catalyst for enantioselective alkene epoxidation in the first step, coupled with a halohydrin dehalogenase (HHDH)-catalysed regioselective epoxide ring opening in the second step for the synthesis of chiral aliphatic non-terminal azidoalcohols. Through the controlled formation of two new stereocenters, corresponding azidoalcohol products could be obtained with high regioselectivity and excellent enantioselectivity (99% ee) in the StyAB-HHDH cascade, while product enantiomeric excesses in the Shi-HHDH cascade ranged between 56 and 61%., BT/Biocatalysis

Published
2021
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11. Combining Photo-Organo Redox- and Enzyme Catalysis Facilitates Asymmetric C-H Bond Functionalization

Author

Zhang, W. (author), Fernandez Fueyo, E. (author), Hollmann, F. (author), Leemans Martin, L. (author), Pesic, M. (author), Wardenga, Rainer (author), Höhne, Matthias (author), Schmidt, S. (author), Zhang, W. (author), Fernandez Fueyo, E. (author), Hollmann, F. (author), Leemans Martin, L. (author), Pesic, M. (author), Wardenga, Rainer (author), Höhne, Matthias (author), and Schmidt, S. (author)

Abstract

In this study, we combined photo-organo redox catalysis and biocatalysis to achieve asymmetric C–H bond functionalization of simple alkane starting materials. The photo-organo catalyst anthraquinone sulfate (SAS) was employed to oxyfunctionalise alkanes to aldehydes and ketones. We coupled this light-driven reaction with asymmetric enzymatic functionalisations to yield chiral hydroxynitriles, amines, acyloins and α-chiral ketones with up to 99 % ee. In addition, we demonstrate functional group interconversion to alcohols, esters and carboxylic acids. The transformations can be performed as concurrent tandem reactions. We identified the degradation of substrates and inhibition of the biocatalysts as limiting factors affecting compatibility, due to reactive oxygen species generated in the photocatalytic step. These incompatibilities were addressed by reaction engineering, such as applying a two-phase system or temporal and spatial separation of the catalysts. Using a selection of eleven starting alkanes, one photo-organo catalyst and 8 diverse biocatalysts, we synthesized 26 products and report for the model compounds benzoin and mandelonitrile > 97 % ee at gram scale., BT/Biocatalysis, BN/Greg Bokinsky Lab

Published
2018
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12. Diastereoselective Hydrolysis of Branched Malonate Diesters by Porcine Liver Esterase: Synthesis of 5‐Benzyl‐Substituted Cα‐Methyl‐β‐proline and Catalytic Evaluation

Author

Kotapati, Hari Kiran, primary, Robinson, Jamarii D., additional, Lawrence, Daniel R., additional, Fortner, Kimberly R., additional, Stanford, Caleb W., additional, Powell, Douglas R., additional, Wardenga, Rainer, additional, Bornscheuer, Uwe T., additional, and Masterson, Douglas S., additional

Published
2017
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13. Combining Photo‐Organo Redox‐ and Enzyme Catalysis Facilitates Asymmetric C‐H Bond Functionalization.

Author

Zhang, Wuyuan, Fueyo, Elena Fernandez, Hollmann, Frank, Martin, Laura Leemans, Pesic, Milja, Wardenga, Rainer, Höhne, Matthias, and Schmidt, Sandy

Subjects
ALKANES, KETONES, BIOCATALYSIS, HYDROGEN bonding, CHEMICAL reactions
Abstract

In this study, we combined photo‐organo redox catalysis and biocatalysis to achieve asymmetric C–H bond functionalization of simple alkane starting materials. The photo‐organo catalyst anthraquinone sulfate (SAS) was employed to oxyfunctionalise alkanes to aldehydes and ketones. We coupled this light‐driven reaction with asymmetric enzymatic functionalisations to yield chiral hydroxynitriles, amines, acyloins and α‐chiral ketones with up to 99 % ee. In addition, we demonstrate functional group interconversion to alcohols, esters and carboxylic acids. The transformations can be performed as concurrent tandem reactions. We identified the degradation of substrates and inhibition of the biocatalysts as limiting factors affecting compatibility, due to reactive oxygen species generated in the photocatalytic step. These incompatibilities were addressed by reaction engineering, such as applying a two‐phase system or temporal and spatial separation of the catalysts. Using a selection of eleven starting alkanes, one photo‐organo catalyst and 8 diverse biocatalysts, we synthesized 26 products and report for the model compounds benzoin and mandelonitrile > 97 % ee at gram scale. Joint forces! The combination of a photo‐organo catalyst with 8 diverse biocatalysts achieves asymmetric C–H bond functionalization of simple alkane starting materials to hydroxynitriles, amines, acyloins, α‐chiral ketones, and transformation into alcohols, esters and carboxylic acids. [ABSTRACT FROM AUTHOR]

Published
2019
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