We have developed a method for the site-selective hydrogenation of unactivated alkenes using 8-aminoquinoline amide as the directing group. For unactivated alkenes with two C-C double bonds, Daugulis's 8-aminoquinoline amide facilitated the site-selective hydrogenation of the desired C-C double bond, producing a product in which one C-C double bond was reduced. Site-selective reduction methodologies using intramolecular directing groups are expected to contribute significantly to the synthesis of molecules with multiple reducible functional groups in the future.
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http://dx.doi.org/10.1248/cpb.c24-00433 | DOI Listing |
Org Lett
January 2025
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
4'-Selective alkylation of nucleosides has been recognized as one of the ideal and straightforward approaches to chemically modified nucleosides, but such a transformation has been scarce and less explored. In this Letter, we combine a visible-light-mediated photoredox catalysis and hydrogen atom transfer (HAT) auxiliary to achieve β-C(sp)-H alkylation of alcohol on tetrahydrofurfuryl alcohol scaffolds and exploit it for 4'-selective alkylation of nucleosides. The reaction involves an intramolecular 1,5-HAT process and stereocontrolled Giese addition of the resultant radicals.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Institut für Chemie, Technische Universität Chemnitz, Straße der Nationen 62, 09111 Chemnitz, Germany.
We present a bifunctional catalyst consisting of a copper(I)/N-heterocyclic carbene and an organocatalytic guanidine moiety that enables, for the first time, a copper(I)-catalyzed reduction of amides with H as the terminal reducing agent. The guanidine allows for reactivity tuning of the originally weakly nucleophilic copper(I) hydrides - formed in situ - to be able to react with difficult-to-reduce amides. Additionally, the guanidine moiety is key for the selective recognition of "privileged" amides based on simple and readily available heterocycles in the presence of other amides within one molecule, giving rise to hitherto unknown site-selective catalytic amide hydrogenation.
View Article and Find Full Text PDFNat Commun
January 2025
School of Chemistry, Chemical Engineering, and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore.
Acylation stands as a fundamental process in both biological pathways and synthetic chemical reactions, with acylated saccharides and their derivatives holding diverse applications ranging from bioactive agents to synthetic building blocks. A longstanding objective in organic synthesis has been the site-selective acylation of saccharides without extensive pre-protection of alcohol units. In this study, we demonstrate that by simply altering the chirality of N-heterocyclic carbene (NHC) organic catalysts, the site-selectivity of saccharide acylation reactions can be effectively modulated.
View Article and Find Full Text PDFChimia (Aarau)
December 2024
College of Science and Engineering, Hamad Bin Khalifa University, P.O. Box: 34110, Doha, Qatar.
Demand for lithium is expected to quadruple by the end of the decade. Without new sources of production, the supply-demand curve is expected to invert. Traditional geological reserves will not be able to meet the anticipated gap, thus unconventional sources of lithium will need to be utilized, setting the stage for fierce competition for perhaps the most critical of mineral resources required for the energy transition.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Materials Science WW4-LKO, Friedrich-Alexander-University of Erlangen-Nuremberg, Martensstrasse 7, 91058, Erlangen, Germany.
The use of metal single atoms (SAs) as co-catalysts on semiconductors has emerged as a promising technology to enhance their photocatalytic hydrogen production performance. In this study, we describe the deposition of very low amounts of Pt SAs (<0.1 at %) on exfoliated graphitic carbon nitride (CN) by a direct Pt-deposition approach from highly dilute chloroplatinic acid precursors.
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