Ketoreductases in the synthesis of valuable chiral intermediates: application in the synthesis of α-hydroxy β-amino and β-hydroxy γ-amino acids

Ketoreductase Catalyzed (Dynamic) Kinetic Resolution for Biomanufacturing of Chiral Chemicals

Biocatalyzed asymmetric reduction of ketones is an environmentally friendly approach and one of the most cost-effective routes for producing chiral alcohols. In comparison with the well-studied reduction of prochiral ketones to generate chiral alcohols with one chiral center, resolution of racemates by ketoreductases (KREDs) to produce chiral compounds with at least two chiral centers is also an important strategy in asymmetric synthesis. The development of protein engineering and the combination with chemo-catalysts further enhanced the application of KREDs in the efficient production of chiral alcohols with high stereoselectivity. This review discusses the advances in the research area of KRED catalyzed asymmetric synthesis for biomanufacturing of chiral chemicals with at least two chiral centers through the kinetic resolution (KR) approach and the dynamic kinetic resolution (DKR) approach.

Access to chiral α-substituted-β-hydroxy arylphosphonates enabled by biocatalytic dynamic reductive kinetic resolution

Ketoreductase (KRED)-catalyzed dynamic reductive kinetic resolution (DYRKR) of α-substituted-β-keto arylphosphonates was developed as a generic and stereoselective approach to synthesize chiral α-substituted-β-hydroxy arylphosphonates, with moderate-to-excellent isolated yield (up to 96%), good-to-excellent diastereoselectivity (up to >99 : <1 dr), and excellent enantioselectivity (up to >99% ee) being achieved.

Biocatalytic dynamic kinetic reductive resolution with ketoreductase from Klebsiella pneumoniae: the asymmetric synthesis of functionalized tetrahydropyrans

Ketoreductase from growing cells of Klebsiella pneumoniae (NBRC 3319) acts as an efficient reagent for converting racemic α-benzyl/cinnamyl substituted-β-ketoesters to the corresponding β-hydroxy esters with excellent yields and stereoselectivities (ee and de >99 %). The reactions described herein followed a biocatalytic dynamic kinetic reductive resolution (DKRR) pathway, which is reported for the first time with such substrates. It was found that the enzyme system can accept substituted mono-aryl rings with different electronic natures. In addition, it also accepts a substituted naphthyl ring and heteroaryl ring in the α-position of the parent β-ketoester. The synthesized enantiopure β-hydroxy esters were then synthetically manipulated to valuable tetrahydropyran building blocks.

Exploiting Enzymatic Dynamic Reductive Kinetic Resolution (DYRKR) in Stereocontrolled Synthesis

Over the past two decades, the domains of both frontline synthetic organic chemistry and process chemistry and have seen an increase in crosstalk between asymmetric organic/organometallic approaches and enzymatic approaches to stereocontrolled synthesis. This review highlights the particularly auspicious role for dehydrogenase enzymes in this endeavor, with a focus on dynamic reductive kinetic resolutions (DYRKR) to "deracemize" building blocks, often setting two stereocenters in so doing. The scope and limitations of such dehydrogenase-mediated processes are overviewed, as are future possibilities for the evolution of enzymatic DYRKR.

An approach to asymmetric synthesis of β-aryl alanines by Pd(0)-catalyzed cross-coupling and cyanate-to-isocyanate rearrangement

A new method for the asymmetric synthesis of β-aryl alanines is reported.

Asymmetric Synthesis of Highly Substituted γ-Amino Acids from Allyltitanium Sulfoximines

[structure: see text]. Asymmetric syntheses of the highly substituted protected gamma-amino acids 10a, 10b, 18, and 21 have been developed starting from the allyltitanium sulfoximines V and VI, respectively, and furan-2-carbaldehyde.

Highly stereoselective reductions of alpha-alkyl-1,3-diketones and alpha-alkyl-beta-keto esters catalyzed by isolated NADPH-dependent ketoreductases

[reaction: see text] The biocatalytic reduction of alpha-alkyl-1,3-diketones and alpha-alkyl-beta-keto esters employing 1 of 20 different isolated NADPH-dependent ketoreductases proved to be a highly efficient method for the preparation of optically pure keto alcohols or hydroxy esters.