1. Chemoenzymatic Cascades toward Aliphatic Nitriles Starting from Biorenewable Feedstocks
- Author
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Michael Stricker, Alessa Hinzmann, and Harald Gröger
- Subjects
biology ,Renewable Energy, Sustainability and the Environment ,Chemistry ,General Chemical Engineering ,Biorenewables ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,TEMPO-oxidation ,Cofactor ,0104 chemical sciences ,Aldoxime dehydratase ,Nitriles ,Cascade reactions ,biology.protein ,Environmental Chemistry ,Organic chemistry ,0210 nano-technology - Abstract
A modern concept of producing nitriles involves aldoxime dehydratases, which are capable of dehydrating aldoximes to the corresponding nitriles without need of a cofactor. Aldoximes as the starting material for nitrile synthesis are easily prepared by condensation of hydroxylamine with the corresponding aldehydes. In this contribution we present chemoenzymatic cascade reactions toward nitriles consisting of an initial nitroxyl radical-catalyzed oxidation of aliphatic alcohols to aldehydes using sodium hypochlorite as the oxidation agent, subsequent condensation of the aldehyde with hydroxylamine, and a biocatalytic dehydration using aldoxime dehydratases to the corresponding nitriles without isolation of intermediates and using the product nitrile as a solvent. These formal "solvent-free" cascades open up the possibility to use biorenewable sources, namely fatty acids, as the starting material for a chemoenzymatic nitrile synthesis. We were also able to apply this cascade concept for the synthesis of aliphatic dinitriles, which are used as, e.g., a precursor for polymer building blocks. Overall yields without isolation of intermediates of up to 70% with very simple product isolation were achieved.
- Published
- 2020
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