The photochemically induced coupling of aromatic ketones with cyclic ethers such as tetrahydrofuran, tetrahydropyran, and 1,4-dioxane was studied. Direct photolysis of the substrates with UV-A light centered at 350 nm does not lead to photoinduced hydrogen transfer whereas the addition of a mixture of the Lewis acid catalysts Ti(O(i)Pr)4 and BF3 enables the formation of the hydroxyalkylation products.
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http://dx.doi.org/10.1021/acs.joc.6b01085 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, China.
Frustrated Lewis pair chemistry (FLP) occupy a crucial position in nonmetal-mediated catalysis, especially toward activation of inert gas molecules. Yet, one formidable issue of homogeneous FLP catalysts is their instability on preservation and recycling. Here we contribute a general solution that marries the polyhedral oligomeric silsesquioxane (POSS) with a structurally specific frustrated Lewis acid to fabricate porous polymer networks, which can form water-insensitive heterogeneous FLP catalysts upon employing Lewis base substrates.
View Article and Find Full Text PDFFoods
January 2025
College of Agriculture, Science and Technology, Delaware State University, 1200 North DuPont Highway, Dover, DE 19901, USA.
Due to an increased demand for natural food additives, clove oil was assessed as a natural alternative to chemical disinfectants in produce washing. This study assessed the antimicrobial activity of 5 and 10% (/) clove oil-amended wash liquid (CO) using a zone of inhibition (ZIB) test and determined the time required to completely inactivate pathogenic bacteria using bacterial death curve analysis. A washing experiment was used to evaluate CO's ability to inhibit bacterial growth on inoculated RTE spinach and in the wash water.
View Article and Find Full Text PDFNat Commun
January 2025
The Picower Institute for Learning and Memory, MIT, Cambridge, MA, USA.
Many essential proteins require pyridoxal 5'-phosphate, the active form of vitamin B6, as a cofactor for their activity. These include enzymes important for amino acid metabolism, one-carbon metabolism, polyamine synthesis, erythropoiesis, and neurotransmitter metabolism. A third of all mammalian pyridoxal 5'-phosphate-dependent enzymes are localized in the mitochondria; however, the molecular machinery involved in the regulation of mitochondrial pyridoxal 5'-phosphate levels in mammals remains unknown.
View Article and Find Full Text PDFChempluschem
January 2025
University of Vienna, Faculty of Chemistry, Währinger Str. 17, 1090, Vienna, AUSTRIA.
The Lewis acid-catalyzed coupling of alkenes and aldehydes presents a modern, versatile synthetic alternative to classical carbonyl addition chemistry, offering exceptional regio- and stereoselectivity. In this work, we present a comprehensive computational investigation into the reaction mechanism of this transformation. Our findings confirm the occurrence of an enantioselective trans-annular [1,5]-hydride shift step and demonstrate that the enantioselectivity of the reaction arises predominantly from steric clashes between functional groups in the cyclization step.
View Article and Find Full Text PDFActa Crystallogr C Struct Chem
February 2025
Department Chemie, Ludwig-Maximilians Universität, Butenandtstrasse 5-13 (Haus D), D-81377 München, Germany.
Acyl fluorides and acyl cations represent typical reactive intermediates in organic reactions, such as Friedel-Crafts acylation. However, the comparatively stable phenyl-substituted compounds have not been fully characterized yet, offering a promising backbone. Attempts to isolate the benzoacylium cation have only been carried out starting from the acyl chloride with weaker chloride-based Lewis acids.
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