Biocatalytic Transamination of Aldolase-Derived 3-Hydroxy Ketones.

Although optical pure amino alcohols are in high demand due to their widespread applicability, they still remain challenging to synthesize, since commonly elaborated protection strategies are required. Here, a multi-enzymatic methodology is presented that circumvents this obstacle furnishing enantioenriched 1,3-amino alcohols out of commodity chemicals. A Type I aldolase forged the carbon backbone with an enantioenriched aldol motif, which was subsequently subjected to enzymatic transamination.

Biocatalytic Synthesis of Homochiral 2-Hydroxy-4-butyrolactone Derivatives by Tandem Aldol Addition and Carbonyl Reduction.

Chiral 2-hydroxy acids and 2-hydroxy-4-butyrolactone derivatives are structural motifs often found in fine and commodity chemicals. Here, we report a tandem biocatalytic stereodivergent route for the preparation of these compounds using three stereoselective aldolases and two stereocomplementary ketoreductases using simple and achiral starting materials. The strategy comprises (i) aldol addition reaction of 2-oxoacids to aldehydes using two aldolases from , 3-methyl-2-oxobutanoate hydroxymethyltransferase (KPHMT ), 2-keto-3-deoxy-l-rhamnonate aldolase (YfaU ), and --hydroxybenzylidene pyruvate hydratase-aldolase from (HBPA ) and (ii) subsequent 2-oxogroup reduction of the aldol adduct by ketopantoate reductase from (KPR ) and a Δ-piperidine-2-carboxylate/Δ-pyrroline-2-carboxylate reductase from pv.

Synthesis of γ-Hydroxy-α-amino Acid Derivatives by Enzymatic Tandem Aldol Addition-Transamination Reactions.

Three enzymatic routes toward γ-hydroxy-α-amino acids by tandem aldol addition-transamination one-pot two-step reactions are reported. The approaches feature an enantioselective aldol addition of pyruvate to various nonaromatic aldehydes catalyzed by --hydroxybenzylidene pyruvate hydratase-aldolase (HBPA) from . This affords chiral 4-hydroxy-2-oxo acids, which were subsequently enantioselectively aminated using -selective transaminases.