Organoborons have recently received much attention, while a biocatalytic platform for the synthesis of chiral organoborons is limited only to cytochrome . In this study, we exploited the other heme protein, neuroglobin (Ngb), and engineered a quadruple mutant, A15C/H64G/V68F/F28M Ngb, by redesigning the heme active site using the structural information on A15C Ngb and molecular docking studies. The enzyme was shown to be efficient in catalyzing carbene transfer B-H insertion reactions between pyridine/quinoline boranes and benzyl 2-diazopropanoates and their derivatives (29 examples). The designed cavity in the heme distal site favors the binding of large volume substrates such as those containing a quinoline, naphthyl, or biphenyl group. As further determined by the X-ray crystallography of , the chiral products are in the -configuration, with up to 98:2 e.r. Furthermore, both the whole cell and cell lysate containing the enzyme are reactive toward the B-H insertion reactions. This study presents a convenient biocatalytic platform that may be generally applicable for the synthesis of functional chiral organoborons.
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http://dx.doi.org/10.1021/acs.orglett.4c03314 | DOI Listing |
JACS Au
October 2024
Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
This study aims to develop a method for the chiral analysis of organoboron compounds using nuclear magnetic resonance (NMR) spectroscopy. It addresses the longstanding challenge associated with these chiral organoboron compounds, which often require derivatization and pretreatment prior to chromatographic analysis. Our method utilizes tridentate ligands to facilitate effective ligand exchange and incorporates fluorine labels, allowing for the precise discrimination of F NMR signals.
View Article and Find Full Text PDFNat Commun
October 2024
Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
Axially chiral allenes bearing organoboron groups are highly sought-after building blocks in organic synthesis due to their potential for generating a wide range of axially and centrally chiral molecules. However, the existing methods for preparing axially chiral allenes containing boron group are primarily limited to the synthesis of allenyl boronic esters, and strategies for accessing axially chiral homoallenyl boronic esters are still scarce. Here, we report the general method for synthesizing axially chiral α-boryl-homoallenyl boronic esters through a highly regio- and stereoselective copper-mediated S2'-addition of newly prepared (diborylalkyl)copper species to chiral propargyl electrophiles.
View Article and Find Full Text PDFOrg Lett
October 2024
Hengyang Medical School, University of South China, Hengyang 421001, China.
Organoborons have recently received much attention, while a biocatalytic platform for the synthesis of chiral organoborons is limited only to cytochrome . In this study, we exploited the other heme protein, neuroglobin (Ngb), and engineered a quadruple mutant, A15C/H64G/V68F/F28M Ngb, by redesigning the heme active site using the structural information on A15C Ngb and molecular docking studies. The enzyme was shown to be efficient in catalyzing carbene transfer B-H insertion reactions between pyridine/quinoline boranes and benzyl 2-diazopropanoates and their derivatives (29 examples).
View Article and Find Full Text PDFNat Commun
October 2024
Shanghai Key Laboratory of Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240, Shanghai, P. R. China.
Org Lett
October 2024
Department of Inorganic and Organic Chemistry, Section of Organic Chemistry, University of Barcelona, carrer Martí i Franquès 1, 08028 Barcelona, Spain.
Herein we describe the organocatalytic asymmetric allylic benzylborylation of allyl fluorides with α-silyl benzylboronic esters. The catalytic protocol leverages the singular features of fluoride as an unconventional leaving group, enabling the catalytic generation of reactive α-boryl carbanion species through desilylative activation. It allows the construction of a wide set of homoallylic benzylated organoboronates bearing two contiguous stereocenters.
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