The proton of alcohols as the sole hydrogen source in diboron-mediated nickel-catalyzed asymmetric transfer hydrogenation of cyclic -sulfonyl imines has been developed, providing the chiral cyclic sulfamidates in excellent enantioselectivities. The mechanistic investigations suggested that the proton of alcohols could be activated by tetrahydroxydiboron to form active nickel hydride species.
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http://dx.doi.org/10.1021/acs.joc.3c01773 | DOI Listing |
Carbohydr Polym
March 2025
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Quzhou Institute for Innovation in Resource Chemical Engineering, Quzhou 324000, China. Electronic address:
Hermetia illucens, with a short growth cycle, is promising as a valuable source of chitin. However, the optimal method for extracting chitin from this insect and its application for hemostasis has not been addressed. This work employed an environmentally friendly choline chloride-lactic acid deep eutectic solvent technology to extract chitin effectively from the Hermetia illucens pupae shells, realizing one-step removal of inorganic salts and proteins.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China.
Chromophores incorporated into rigid polymer matrices may exhibit novel photophysical properties distinct from those in liquid solutions. In this work, we explored the decay path of the second ππ* state (2ππ*) of riboflavin in poly(vinyl alcohol) (PVA) solutions and films with various acidities. Highly efficient internal conversion from 2ππ* to the lowest ππ* state (1ππ*) induced by slight in-plane motion is demonstrated in all PVA solutions and films, irrespective of environmental acidity and rigidification.
View Article and Find Full Text PDFChemistry
January 2025
TU Chemnitz: Technische Universitat Chemnitz, Insitut für Chemie, Straße der Nationen 62, 09111, Chemnitz, GERMANY.
The intramolecular migration of three hydrogen atoms from one moiety of a gaseous radical cation to the other prior to fragmentation is an extremely rare type of redox reaction. Within the scope of this investigation, this scenario requires an ionized but electron-rich arene acceptor bearing a para-(3-hydroxyalkyl) residue. The precise mechanism of such unidirectional 3H transfer processes, including the order of the individual H transfer steps, has remained unclear in spite of previous isotope labelling and recent infrared ion spectroscopy (IRIS) studies.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Yunnan University, Key Laboratory of Medicinal Chemistry for Natural Resources, Ministry of Education, East Outer Ring Road, 650500, Kunming, CHINA.
The reduction of carboxylic esters to aldehydes and alcohols is a fundamental functional group transformation in chemistry. However, the inertness of carbonyl group and the instability of ketyl radical anion intermediate impede the reduction of carboxylic esters via photochemical strategy. Herein, we described the reduction of aliphatic carboxylic esters with synergistic dual photocatalysis via phenolate-catalyzed single electron transfer process and thiol-catalyzed hydrogen atom transfer process.
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, Indian Institute of Technology, Roorkee, Uttarakhand 247667, India.
A photoacid-catalyzed method for esterification is proposed wherein eosin Y is introduced as a photoacid and photoredox catalyst that can be activated with visible light and catalyze the esterification of carboxylic acids. The strategy presented here revealed that proton-coupled electron transfer (PCET) between eosin Y and carboxylic acid might facilitate the formation of a transient ketyl radical. This ketyl radical would subsequently undergo a single electron transfer and then couple with alkyl alcohols, yielding carboxylic esters in good to excellent yields.
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