Biocatalytic Asymmetric Synthesis of N -Aryl-Functionalized Amino Acids and Substituted Pyrazolidinones

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High Resolution Image Download MS PowerPoint Slide N -arylated α-amino acids and pyrazolidin-3-ones are widely being used as chiral building blocks for pharmaceuticals and agrochemicals. Here we report a biocatalytic route for the asymmetric synthesis of various N -arylated aspartic acids applying ethylenediamine- N, N ′-disuccinic acid lyase (EDDS lyase) as a biocatalyst. This enzyme shows a broad substrate scope, enabling the addition of a variety of arylamines to fumarate with high conversions, yielding the corresponding N -arylated aspartic acids in good isolated yields and with high enantiomeric excess (ee > 99%). Furthermore, we developed a chemoenzymatic method toward the synthetically challenging chiral 2-aryl-5-carboxylpyrazolidin-3-ones, using arylhydrazines as bis-nucleophilic donors in the EDDS lyase catalyzed hydroamination of fumarate followed by an acid-catalyzed intramolecular amidation, achieving good overall yields and high optical purity (ee > 99%). In addition, we successfully combined the EDDS lyase catalyzed hydroamination and acid-catalyzed cyclization steps in one pot, thus providing a simple chemoenzymatic cascade route for synthesis of enantiomerically pure pyrazolidin-3-ones. Hence, these biocatalytic methods provide convenient alternative routes to important chiral N -arylated aspartic acids and difficult 2-aryl-5-carboxylpyrazolidin-3-ones.