Biocatalytic cascades are uniquely powerful for the efficient, asymmetric synthesis of bioactive compounds. However, high substrate specificity can hinder the scope of biocatalytic cascades because the constituent enzymes may have non-complementary activity. In this study, we implemented a substrate multiplexed screening (SUMS) based directed evolution approach to improve the substrate scope overlap between a transaldolase (ObiH) and a decarboxylase for the production of chiral 1,2-amino alcohols. To generate a promiscuous cascade, we engineered a tryptophan decarboxylase to act efficiently on β-OH amino acids while avoiding activity on l-threonine, which is needed for ObiH activity. We leveraged this exquisite selectivity with matched substrate scope to produce a variety of enantiopure 1,2-amino alcohols in a one-pot cascade from aldehydes or styrene oxides. This demonstration shows how SUMS can be used to guide the development of promiscuous, C-C bond forming cascades.
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http://dx.doi.org/10.1002/anie.202212637 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Dalian University of Technology, School of Chemical Engineering, No 2 Linggong Road,Ganjingzi District, 116024, Dalian, CHINA.
The Pd-catalyzed asymmetric hydrogenolysis rearrangement of allylic acetates using (s-Bu)3BHK has been described, achieving the synthesis of axially chiral alkylidene cycloalkanes with excellent enantioselectivities (up to 99% ee) and a wide substrate scope (30 examples of cyclohexanes and cyclobutanes). To the best of our knowledge, this is the first time to achieve synthesis of axially chiral olefins via asymmetric hydrogenolysis of allylic acetates. This methodology not only offers a novel synthetic pathway for non-atropisomeric axially chiral structures but also highlights the potential of asymmetric hydrogenolysis as a powerful tool in synthetic organic chemistry.
View Article and Find Full Text PDFOrg Lett
January 2025
College of Materials and Energy, South China Agricultural University, 510642 Guangzhou, China.
We report herein a robust enantioselective ring opening coupling of oxabenzonorbornadienes via Pd(II)-catalyzed domino cyclization of alkynylanilines, which features the formation of three covalent bonds and two contiguous stereocenters with excellent enantio- and diastereoselectivity and a broad substrate scope. The good functional group tolerance of this domino desymmetrization strategy enables efficient late-stage transformation of natural product-derived alkynylanilines. The resulting indolated dihydronaphthols could serve as a valuable platform to streamline the diversity-oriented synthesis of other valuable enantioenriched tetrahydronaphthalene derivatives.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Pharmacy, College of Pharmacy, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea.
In this study, we developed palladium-catalyzed dehydrogenative cyclization to transform 1-(2-aminoaryl)-3-arylpropan-1-ones into 2-arylquinolin-4(1)-ones, also known as aza-flavones which are the bioisosteres of flavones, in an atom-economic manner. This method exhibited excellent chemical compatibility with a broad substrate scope, accommodating up to 25 derivatives. Additionally, kinetic studies were performed to elucidate the reaction mechanism.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan.
An electrochemical method for the oxidative dearomatization of electron-deficient phenols by employing tetrabutylammonium bromide as a mediator under aqueous biphasic conditions is reported. This approach represents a safer alternative to the use of stoichiometric chemical oxidants and enables oxidative dearomative spirolactonization and spiroetherification reactions. Compared to previous approaches based on direct electrolysis, this strategy expands the substrate scope to electron-deficient phenols.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
State Key Laboratory of New Pharmaceutical Preparations and Excipients, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Materials Science, Hebei University, Baoding, Hebei, 071002, P. R. China.
Herein, we describe a visible-light-mediated selenocyclization of -vinylanilides with diselenides, which provides a mild and effective method for the synthesis of selenylated 4-3,1-benzoxazines. This reaction proceeds under metal-free conditions, without the need for a chemical oxidant or a controlled O atmosphere and shows a broad substrate scope with yields of up to 98%. Additionally, the process is easily scalable to the gram scale.
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