54542-13-1Relevant articles and documents
Synthesis of Chiral Amines via a Bi-Enzymatic Cascade Using an Ene-Reductase and Amine Dehydrogenase
Jongkind, Ewald P. J.,Fossey-Jouenne, Aurélie,Mayol, Ombeline,Zaparucha, Anne,Vergne-Vaxelaire, Carine,Paul, Caroline E.
, (2021/12/23)
Access to chiral amines with more than one stereocentre remains challenging, although an increasing number of methods are emerging. Here we developed a proof-of-concept bi-enzymatic cascade, consisting of an ene reductase and amine dehydrogenase (AmDH), to afford chiral diastereomerically enriched amines in one pot. The asymmetric reduction of unsaturated ketones and aldehydes by ene reductases from the Old Yellow Enzyme family (OYE) was adapted to reaction conditions for the reductive amination by amine dehydrogenases. By studying the substrate profiles of both reported biocatalysts, thirteen unsaturated carbonyl substrates were assayed against the best duo OYE/AmDH. Low (5 %) to high (97 %) conversion rates were obtained with enantiomeric and diastereomeric excess of up to 99 %. We expect our established bi-enzymatic cascade to allow access to chiral amines with both high enantiomeric and diastereomeric excess from varying alkene substrates depending on the combination of enzymes.
Generation of Oxidoreductases with Dual Alcohol Dehydrogenase and Amine Dehydrogenase Activity
Tseliou, Vasilis,Schilder, Don,Masman, Marcelo F.,Knaus, Tanja,Mutti, Francesco G.
supporting information, p. 3315 - 3325 (2020/12/11)
The l-lysine-?-dehydrogenase (LysEDH) from Geobacillus stearothermophilus naturally catalyzes the oxidative deamination of the ?-amino group of l-lysine. We previously engineered this enzyme to create amine dehydrogenase (AmDH) variants that possess a new hydrophobic cavity in their active site such that aromatic ketones can bind and be converted into α-chiral amines with excellent enantioselectivity. We also recently observed that LysEDH was capable of reducing aromatic aldehydes into primary alcohols. Herein, we harnessed the promiscuous alcohol dehydrogenase (ADH) activity of LysEDH to create new variants that exhibited enhanced catalytic activity for the reduction of substituted benzaldehydes and arylaliphatic aldehydes to primary alcohols. Notably, these novel engineered dehydrogenases also catalyzed the reductive amination of a variety of aldehydes and ketones with excellent enantioselectivity, thus exhibiting a dual AmDH/ADH activity. We envisioned that the catalytic bi-functionality of these enzymes could be applied for the direct conversion of alcohols into amines. As a proof-of-principle, we performed an unprecedented one-pot “hydrogen-borrowing” cascade to convert benzyl alcohol to benzylamine using a single enzyme. Conducting the same biocatalytic cascade in the presence of cofactor recycling enzymes (i.e., NADH-oxidase and formate dehydrogenase) increased the reaction yields. In summary, this work provides the first examples of enzymes showing “alcohol aminase” activity.
Ruthenium Catalyzed Direct Asymmetric Reductive Amination of Simple Aliphatic Ketones Using Ammonium Iodide and Hydrogen
Ernst, Martin,Ghosh, Tamal,Hashmi, A. Stephen K.,Schaub, Thomas
supporting information, (2020/07/14)
The direct conversion of ketones into chiral primary amines is a key transformation in chemistry. Here, we present a ruthenium catalyzed asymmetric reductive amination (ARA) of purely aliphatic ketones with good yields and moderate enantioselectivity: up to 99 percent yield and 74 percent ee. The strategy involves [Ru(PPh3)3H(CO)Cl] in combination with the ligand (S,S)-f-binaphane as the catalyst, NH4I as the amine source and H2 as the reductant. This is a straightforward and user-friendly process to access industrially relevant chiral aliphatic primary amines. Although the enantioselectivity with this approach is only moderate, to the extent of our knowledge, the maximum ee of 74 percent achieved with this system is the highest reported till now apart from enzyme catalysis for the direct transformation of ketones into chiral aliphatic primary amines.
