Oligosaccharide syntheses are an important source of well-defined sugar constructs particularly needed for the evaluation of structure-activity relationships. The chemical assembly of oligosaccharides requires several building blocks, that is, glycosyl donors and acceptors, which are prepared in multistep processes and in a generally tedious and time-consuming manner. Having developed one-pot procedures meant to minimise the effort in sugar building block preparation, we tackled herein the one-pot preparation of fully protected and 2-, 3-, 4-, and 6-alcohol derivatives of d-mannose, a widely distributed monosaccharide. As a consequence of the hydroxyl group pattern of D-mannose, regioselective and stereoselective benzylidenations were developed and later seamlessly utilised as the first transformation in the one-pot procedure.
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http://dx.doi.org/10.1039/c3ob40079d | DOI Listing |
Acc Chem Res
January 2025
Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States.
ConspectusThe manipulation of strained rings is a powerful strategy for accessing the valuable chemical frameworks present in natural products and active pharmaceutical ingredients. Aziridines, the smallest N-containing heterocycles, have long served as building blocks for constructing more complex amine-containing scaffolds. Traditionally, the reactivity of typical aziridines has been focused on ring-opening by nucleophiles or the formation of 1,3-dipoles.
View Article and Find Full Text PDFNat Commun
January 2025
Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, PR China.
Allylic ethers and alcohols are essential structural motifs commonly present in natural products and pharmaceuticals. Direct allylic C-H oxygenation of internal alkenes is one of the most direct methods, bypassing the necessity for an allylic leaving group that is needed in the traditional Tsuji-Trost reaction. Herein, we develop an efficient and practical method for synthesizing (E)-allyl ethers from readily available internal alkenes and alcohols or phenols via selective allylic C-H oxidation.
View Article and Find Full Text PDFChem Sci
December 2024
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609.
As a class of readily available and multifunctional building blocks, the chemistry of 4-alken-2-ynyl carbonates remains to be explored. Presented herein is a palladium-catalysed cascade transformative reaction between 4-alken-2-ynyl carbonates and -functionalised activated alkenes. Achiral 1,1-bisalkyl-4-alken-2-ynyl carbonates undergo highly regioselective propargylic substitution with -hydroxyphenyl-tethered activated alkenes, and an auto-tandem vinylogous addition, unusual central-carbon Tsuji-Trost alkylation, protonation and β-H elimination process is followed to furnish fused and spirocyclic frameworks with high structural complexity.
View Article and Find Full Text PDFAcc Chem Res
January 2025
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
ConspectusIn recent years, our research group has dedicated significant effort to the field of asymmetric organometallic electrochemical synthesis (AOES), which integrates electrochemistry with asymmetric transition metal catalysis. On one hand, we have rationalized that organometallic compounds can serve as molecular electrocatalysts (mediators) to reduce overpotentials and enhance both the reactivity and selectivity of reactions. On the other hand, the conditions for asymmetric transition metal catalysis can be substantially improved through electrochemistry, enabling precise modulation of the transition metal's oxidation state by controlling electrochemical potentials and regulating the electron transfer rate via current adjustments.
View Article and Find Full Text PDFOrg Lett
January 2025
School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan, Hunan 411201, China.
An unprecedented synergistic copper- and amine-catalyzed cyclization of enynone is reported. This reaction features an efficient and straightforward construction of multisubstituted tetralone through an amine-assisted regioselective oxygen atom transfer process and stereoselective intramolecular Michael addition cyclization. Under dehydrative reaction conditions, the synthesis of tetrahydronaphthylimine derivatives with ketone group tolerance is achieved, which could be challenging via traditional methods.
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