This study describes our development of a novel and efficient procedure for C-O bond formation under mild conditions, for coupling heteroaryl chlorides with phenols or primary aliphatic alcohols. We utilized a continuous-flow microfluidic reactor for C-O bond formation in electron-deficient pyrimidines and pyridines in a much more facile manner with a cleaner reaction profile, high yield, quick scalability and without the need for the transition metal catalyst. This approach can be of general utility to make C-O bond containing intermediates of industrial importance in a continuous and safe manner.
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http://dx.doi.org/10.1016/j.tetlet.2016.03.095 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
A small but growing set of radical SAM (-adenosyl-l-methionine) enzymes catalyze the radical mediated dehydration or dehydrogenation of 1,2-diol substrates. In some cases, these activities can be interchanged via minor structural perturbations to the reacting components raising questions regarding the relative importance of hyperconjugation, proton circulation and leaving group stability in determining the reaction outcome. The present work describes trapping and electron paramagnetic resonance (EPR) characterization of an α-hydroxyalkyl radical intermediate during dehydration and dehydrogenation of cytosylglucuronic acid and its derivatives catalyzed by the radical SAM enzyme BlsE and its Glu189Ala mutant from the blasticidin S biosynthetic pathway.
View Article and Find Full Text PDFMolecules
January 2025
Department of Chemistry, Acadia University, Wolfville, NS B4P 2R6, Canada.
A concise, transition metal-free four-step synthetic pathway has been developed for the synthesis of tetracyclic heterosteroidal compounds, 14-aza-12-oxasteroids, starting from readily available 2-naphthol analogues. After conversion of 2-naphthols to 2-naphthylamines by the Bucherer reaction, subsequent selective C-acetylation was achieved via the Sugasawa reaction and reduction of the acetyl group using borohydride, which resulted into the corresponding amino-alcohols. The naphthalene-based amino-alcohols underwent double dehydrations and double intramolecular cyclization with oxo-acids leading to one-pot formation of a C-N bond, a C-O bond and an amide bond in tandem, to generate two additional rings completing the steroidal framework.
View Article and Find Full Text PDFACS Catal
January 2025
Fakultät für Chemie und Pharmazie, Universität Regensburg, Regensburg 93040, Germany.
Transition metal catalysis is crucial for the synthesis of complex molecules, with ligands and bases playing a pivotal role in optimizing cross-coupling reactions. Despite advancements in ligand design and base selection, achieving effective synergy between these components remains challenging. We present here a general approach to nickel-catalyzed photoredox reactions employing -butylamine as a cost-effective bifunctional additive, acting as the base and ligand.
View Article and Find Full Text PDFChemistry
January 2025
Jadavpur University, Chemistry, PG Science building, 700032, Kolkata, INDIA.
Over the past few decades, the merger of photocatalysis and transition metal-based catalysis or self-photoexcitation of transition metals has emerged as a useful tool in organic transformations. In this context, cobalt-based systems have attracted significant attention as sustainable alternatives to the widely explored platinum group heavy metals (iridium, rhodium, ruthenium) for photocatalytic chemical transformations. This review encompasses the basic types of cobalt-based homogeneous photocatalytic systems, their working principles, and the recent developments (2018-2024) in C-X (X = C, N, O, H, Si) bond formations.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Strait Institute of Flexible Electronics (SIFE, Future Technologies), Fujian Normal University and Strait Laboratory of Flexible Electronics (SLoFE), Fuzhou, Fujian 350117, China.
In the CO reduction reactions (CORR), the product selectivity is strongly dependent on the binding energy differences of the key intermediates. Herein, we systematically evaluated the CORR reaction pathways on single transition metal atom doped catalysts TMCu/CuO by density functional theory (DFT) methods and found that *CO is more likely to undergo C-O bond cleavage rather than be hydrogenated on TMCu/CuO (TM = Sc, Ti, V, Cr, Mn, Fe, Co), which facilitates C production with a low-energy pathway of OC-C coupling, while it prefers to be hydrogenated to form CHO on TMCu/CuO (TM = Ni, Cu). The defects of Cu in TMCu/CuO were confirmed to enhance the production of ethanol.
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