Cascade Biocatalysis for Regio- and Stereoselective Aminohydroxylation of Styrenyl Olefins to Enantiopure Arylglycinols

Abstract

Chiral β-amino alcohols are privileged scaffolds frequently found in pharmaceutically active molecules and natural products. Aminohydroxylation of olefins is one of the most powerful strategies to access chiral vicinal amino alcohols. However, the direct regio-and stereoselective aminohydroxylation of olefins to unprotected enantioenriched β-amino alcohols remains a longstanding challenge. Herein, we report that a novel one-pot four-enzyme [styrene monooxygenase (SMO)/epoxide hydrolase (EH)/ alcohol dehydrogenase (ADH)/ω-transaminase (TA)] biocatalytic cascade efficiently catalyzes the direct transformation of readily available styrenyl olefins into unprotected 2-amino-2-phenyl ethanols in good yields and excellent enantioselectivity. In vitro cascade biocatalysis aminohydroxylation of styrenyl olefins was first investigated by the combined four enzymes (SMO/EH/ADH/TA) with a trace amount of NADH (0.02 mM) and pyridoxal-5′-phosphate (0.1 mM), affording both enantiomers of β-amino alcohols 5a−j in 13.9−98.7% conversions and 86−99% ee. Whole-cell-based cascade biocatalysis was achieved by using the constructed recombinant Escherichia coli pairwise combinations and single tailor-made whole-cell biocatalyst without an additional NADH cofactor; (R)-and (S)-β-amino alcohols 5a−j could be obtained in 14.6−99.7% conversions and 86−99% ee. Moreover, the preparative experiments of this new cascade biocatalysis were demonstrated by the single tailor-made whole-cell biocatalyst [E. coli (CGS-DEM) and E. coli (CGS-DEB)] with the substrates 1a−b and 1h in an aqueous-organic two-phase system, affording chiral βamino alcohols [(R)-or (S)-5a−b, h] in good yields (50.9−64.3%) and excellent ee (>99%).

One-pot Synthesis of (R)- and (S)-phenylglycinol From Bio-based L-phenylalanine by an Artificial Biocatalytic Cascade

“…In the fth step, an NAD + dependent alcohol dehydrogenase (GoSCR) from Glucoconobacter oxydans 621H (Cui et al 2017) was selected for oxidation of (S)-diol 5 to 2-HAP 6. In the nal amination step, an (R)-selective ω-transaminase (MVTA) from Mycobacterium vanbaalenii (Zhang et al 2019) and an (S)-selective ωtransaminase (BMTA) from Bacillus megaterium SC6394 (Zhang et al 2020) were employed to convert 2-HAP 6 to (S)-7 and (R)-7, respectively. The NAD + and NADH recycling system was formed in the third and fth step of the catalytic process.…”

“…In the past two decades, various biocatalytic ways have been reported for the synthesis of chiral vicinal amino alcohols, such as racemic amino alcohol kinetic resolution (Wu et al 2017;Rouf et al 2011), chiral amino ketones asymmetric reduction (Patel et al 1993) and α-ketol asymmetric reduction amination (Zhang et al 2019a; Chen et al 2019). Recently, two types of biocatalytic cascades for asymmetric ring-opening of epoxides (Zhang et al 2019b) and asymmetric aminohydroxylation of alkene (Zhang et al 2020) have been developed for the synthesis of chiral vicinal amino alcohols, good conversions (up to 99%) and excellent ee (> 99%) of products were obtained from the tested epoxides and alkenes. Despite the substrates (epoxide and alkene) used in these methods are not expensive and readily available, the epoxides and alkenes are mainly produced from the fossil (non-renewable carbon resources) resource, make these methods less sustainable.…”

Biocatalytic Valorization of Biobased 5-Hydroxymethylfurfural to 5-Hydroxymethyl-2-furfurylamine in a Three-Constituent Deep Eutectic Solvent–Water System

“…Cultivation of ω-TAm Producers. Recombinant Escherichia coli CV, 34 E. coli BMTA, 35 E. coli MVTA, 35 and E. coli AT 36 were cultivated and harvested according to the previously reported procedures. 30 Optimization of Biotransamination Conditions.…”

Asymmetric Synthesis of N‐Substituted 1,2‐Amino Alcohols from Simple Aldehydes and Amines by One‐Pot Sequential Enzymatic Hydroxymethylation and Asymmetric Reductive Amination

“… [11] While the biocatalytic reductive amination of α‐hydroxymethyl ketones offers a straightforward approach to access this class of important compounds, the transformations using transaminases and amine dehydrogenases prefer to form N‐ unfunctionalized 1,2‐amino alcohols. While a couple of transaminases have been reported to accept several α‐hydroxymethyl ketones producing the corresponding amino alcohols, a systematic investigation is lacking for the scope of transaminases accepting α‐hydroxymethyl ketones as the substrate [9d,e,f] . Although an amine dehydrogenase has been tested with primary amines as amino partner for the reductive amination of 4‐fluorophenylacetone, ethylamine and allylamine showed only 15 % and <5 % conversion, respectively, and unsatisfactory enantioselectivity [9b] .…”