Parallel Interconnected Kinetic Asymmetric Transformation (PIKAT) with an Immobilized ω-Transaminase in Neat Organic Solvent

Molecules. 2020 May 3;25(9):2140. doi: 10.3390/molecules25092140.

Abstract

Comprising approximately 40% of the commercially available optically active drugs, α-chiral amines are pivotal for pharmaceutical manufacture. In this context, the enzymatic asymmetric amination of ketones represents a more sustainable alternative than traditional chemical procedures for chiral amine synthesis. Notable advantages are higher atom-economy and selectivity, shorter synthesis routes, milder reaction conditions and the elimination of toxic catalysts. A parallel interconnected kinetic asymmetric transformation (PIKAT) is a cascade in which one or two enzymes use the same cofactor to convert two reagents into more useful products. Herein, we describe a PIKAT catalyzed by an immobilized ω-transaminase (ωTA) in neat toluene, which concurrently combines an asymmetric transamination of a ketone with an anti-parallel kinetic resolution of an amine racemate. The applicability of the PIKAT was tested on a set of prochiral ketones and racemic α-chiral amines in a 1:2 molar ratio, which yielded elevated conversions (up to >99%) and enantiomeric excess (ee, up to >99%) for the desired products. The progress of the conversion and ee was also monitored in a selected case. This is the first report of a PIKAT using an immobilized ωTA in a non-aqueous environment.

Keywords: EziG; PIKAT; aminotransferases; asymmetric catalysis; biocatalysis; cascades; enzyme immobilization; kinetic resolution; transaminases; α-chiral amines.

MeSH terms

  • Amines / chemistry
  • Biocatalysis
  • Enzymes, Immobilized*
  • Ketones / chemistry
  • Kinetics
  • Solvents / chemistry*
  • Substrate Specificity
  • Transaminases / chemistry*

Substances

  • Amines
  • Enzymes, Immobilized
  • Ketones
  • Solvents
  • Transaminases