Enantio-convergent hydrolysis of racemic styrene oxides was achieved to prepare enantiopure (R)-phenyl-1,2-ethanediol by using two recombinant epoxide hydrolases (EHs) of a bacterium, Caulobacter crescentus, and a marine fish, Mugil cephalus. The recombinant C. crescentus EH primarily attacked the benzylic carbon of (S)-styrene oxide, while the M. cephalus EH preferentially attacked the terminal carbon of (R)-styrene oxide, thus leading to the formation of (R)-phenyl-1,2-ethanediol as the main product. (R)-Phenyl-1,2-ethanediol was obtained with 90% enantiomeric excess and yield as high as 94% from 50 mM racemic styrene oxides in a one-pot process.
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http://dx.doi.org/10.1007/s10529-007-9495-2 | DOI Listing |
Chem Commun (Camb)
November 2024
State Key Laboratory of Fine Chemicals, Department of Pharmaceutical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
Org Lett
March 2023
Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, Hangzhou 310058, China.
The organocatalytic asymmetric reactions of C2-unsubstituted racemic naphthyl-indoles with orthoalkynylnaphthols were employed to synthesize axially chiral styrenes connected to an axially chiral naphthyl-indole unit. Utilizing chiral phosphoric acid as the catalyst, these axially chiral styrenes were prepared in good yields (up to 96%) and excellent stereoselectivity (up to >99.9% ee, >20:1 dr, and >99:1 /) in mild conditions.
View Article and Find Full Text PDFACS Polym Au
August 2022
Polymer Science and Engineering Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
The enantioselective separation of a racemic mixture of amino acids was achieved by chiral amino acid-modified polystyrene (PS) that was developed by a post-polymer modification approach. Styrene was polymerized using the reversible addition-fragmentation chain-transfer (RAFT) polymerization technique and further post-polymer modification was applied by Friedel-Crafts acylation reaction with chiral -phthaloyl-l-leucine acid chloride to obtain the protected PS-l-Leu. The chiral PS (protected PS-l-Leu) was assembled into microspheres using a surfactant and was used for carrying out the enantioselective separation of amino acid racemic mixtures by enantioselective adsorption followed by a simple filtration process.
View Article and Find Full Text PDFChemistry
May 2023
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore.
Styrene oxide isomerase (SOI) catalyzes the Meinwald rearrangement of aryl epoxides to carbonyl compounds via a 1,2-trans-shift in a stereospecific manner. A number of cascade biotransformations with SOI-catalyzed epoxide isomerization as a key step have been developed to convert readily available substrates into valuable chiral chemicals. Cascade conversion of terminal or internal alkenes into chiral acids, alcohols or amines was achieved, which involved SOI-catalyzed enantio-retentive isomerization of terminal epoxides via 1,2-H shift, or internal epoxides via 1,2-methyl shift.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2022
Key Laboratory of Biocatalysis & Chiral Drug Synthesis of Guizhou Province, Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, School of Pharmacy, Zunyi Medical University, No.6 West Xuefu Road, Xinpu District, Zunyi City, Guizhou Province, P. R. China.
Optically pure sulfoxides are noteworthy compounds applied in a wide range of industrial fields; however, the biocatalytic deracemization of racemic sulfoxides is challenging. Herein, a high-enantioselective methionine sulfoxide reductase A (MsrA) was combined with a low-enantioselective styrene monooxygenase (SMO) for the cyclic deracemization of sulfoxides. Enantiopure sulfoxides were obtained in >90 % yield and with >90 % enantiomeric excess (ee) through dynamic "selective reduction and non-selective oxidation" cycles.
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