An efficient metal-free method for the synthesis of α-ketothioesters is described for the first time. This reaction features the ability of pyrrolidine to fine-tune the reaction between 2-oxoaldehyde and thiols through iminium to the desired product in moderate to good yields. As an advantage, no external oxidants or metal catalysts are required in our method. Reactions performed under modified conditions lead to an apparent balance in reactivity of secondary amine and thiols toward 2-oxoaldehydes.
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http://dx.doi.org/10.1021/acs.joc.5b02176 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
University of Regensburg, Faculty of Chemistry and Pharmacy, Institute of Inorganic Chemistry, Universitätsstraße 31, D-93053, Regensburg, GERMANY.
Aminophosphates are the focus of research on prebiotic phosphorylation chemistry. Their bifunctional nature also makes them a powerful class of organocatalysts. However, the structural chemistry and dynamics of proton-binding in phosphorylation and organocatalytic mechanisms are still not fully understood.
View Article and Find Full Text PDFEnzymatic asymmetric synthesis of l-phenylglycine by amino acid dehydrogenases has potential for industrial applications; however, this is hindered by their low catalytic efficiency toward high-concentration substrates. We identified and characterized a novel leucine dehydrogenase (LeuDH) with a high catalytic efficiency for benzoylformic acid via directed metagenomic approaches. Further, we obtained a triple-point mutant LeuDH-EER (D332E/G333E/L334R) with improved stability and catalytic efficiency through the rational design of distal loop 13.
View Article and Find Full Text PDFACS Cent Sci
January 2025
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Multicomponent reactions (MCRs), highly sought-after methods to produce atom-, step-, and energy-economic organic syntheses, have been developed extensively. However, catalytic asymmetric MCRs, especially those involving radical species, remain largely unexplored owing to the difficulty in stereoselectively regulating the extraordinarily high reactivity of open-shell radical species. Herein, we report a conceptually novel catalytic asymmetric three-component radical cascade reaction of readily accessible glycine esters, α-bromo carbonyl compounds and 2-vinylcyclopropyl ketones via synergistic photoredox/Brønsted acid catalysis, in which three sequential C-C (σ/π/σ) bond-forming events occurred through a radical addition/ring-opening/radical-radical coupling protocol, affording an array of valuable enantioenriched unnatural α-amino acid derivatives bearing two contiguous stereogenic centers and an alkene moiety in moderate to good yield with high diastereoselectivity, excellent enantioselectivity and good -dominated geometry under mild reaction conditions.
View Article and Find Full Text PDFAnal Methods
January 2025
School of Food and Bioengineering, Changsha University of Science & Technology, Changsha, Hunan, 4100114, China.
A non-derivatized high-performance liquid chromatographic (HPLC) method was developed for the simultaneous quantification of hydroxyl acids and their amination products in ammonolysis reaction mixtures. By optimizing the mobile phase composition and pH (0.04 M KHPO-5% methanol, pH = 2.
View Article and Find Full Text PDFInorg Chem
January 2025
Inner Mongolia Engineering Research Centre of Lithium-Sulfur Battery Energy Storage, Inner Mongolia Key Laboratory of Solid State Chemistry for Battery, College of Chemistry and Materials Science, Inner Mongolia Minzu University, Tongliao 028000, People's Republic of China.
In the era of global warming, the conversion of carbon dioxide into high-value products has become a widely scrutinized emerging mitigation strategy. Metalation of bpy-containing MOF-253 led to the synthesis of MOF-253-0.5Ag, which acts as an efficient catalyst for the carbonylative cyclization of CO with alkyne molecules (such as propynyl alcohols and propynyl amines) at room temperature and ambient CO pressure, yielding the corresponding α-alkyl cyclic carbonates and oxazolidinones, thus endowing the catalytic system with bifunctional characteristics.
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