Taxol is a clinically used drug for the treatment of various types of cancers. Its 6/8/6/4-membered ring (ABCD-ring) system is substituted by eight oxygen functional groups and flanked by four acyl groups, including a β-amino acid side chain. Here we report a 34-step total synthesis of this unusually oxygenated and intricately fused structure. Inter- and intramolecular radical coupling reactions connected the A- and C-ring fragments and cyclized the B-ring, respectively. Functional groups of the A- and C-rings were then efficiently decorated by employing newly developed chemo-, regio-, and stereoselective reactions. Finally, construction of the D-ring and conjugation with the β-amino acid delivered taxol. The powerful coupling reactions and functional group manipulations implemented in the present synthesis provide new valuable information for designing multistep target-oriented syntheses of diverse bioactive natural products.
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http://dx.doi.org/10.1002/anie.202219114 | DOI Listing |
J Am Chem Soc
January 2025
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
Direct cross-coupling reactions between two similar unactivated partners are challenging but constitute a powerful strategy for the creation of new carbon-carbon bonds in organic synthesis. [4]Dendralenes are a class of acyclic branched conjugated oligoenes with great synthetic potential for the rapid generation of structural complexity, yet the chemistry of [4]dendralenes remains an unexplored field due to their limited accessibility. Herein, we report a highly selective palladium-catalyzed oxidative cross-coupling of two allenes with the presence of a directing olefin in one of the allenes, enabling the facile synthesis of a broad range of functionalized [4]dendralenes in a convergent modular manner.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, United States.
Acrylic nitriles are a versatile class of synthetic precursors for a variety of pharmaceutically active compounds, as well as for nitrile polymers. We devised a stereoselective synthesis of ()-acrylic nitriles from the Ru-catalyzed coupling reaction of nitriles with unsaturated carbonyl compounds via C-C bond cleavage. Both carbon KIE and Hammett correlation data indicated that C-C bond cleavage is the rate-determining step for the coupling reaction.
View Article and Find Full Text PDFOrg Lett
January 2025
Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
A 1,1-hydroboration of alkynylgermanes with unique -Ge/B stereochemistry under transition-metal-free conditions is reported. Mechanistic studies suggest that a pathway involving α-boration followed by a stepwise 1,2-Ge/H shift on the intermediate structurally lies between an alkyne-Ge π complex and a typical vinyl cation. The resulting Ge/B bimetallic modules, along with a /Ge/B trimetallic variant, can be conveniently transformed into trisubstituted olefins through iterative divergent cross-coupling.
View Article and Find Full Text PDFSmall
January 2025
College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China.
The transition metal single atoms (SAs)-based catalysts with M-N coordination environment have shown excellent performance in electrocatalytic reduction of CO, and they have received extensive attention in recent years. However, the presence of SAs makes it very difficult to efficiently improve the coordination environment. In this paper, a method of direct high-temperature pyrolysis carbonization of ZIF-8 adsorbed with Ni and Fe ions is reported for the synthesis of Ni SAs and FeN nanoparticles (NPs) supported by the N-doped carbon (NC) hollow nanododecahedras (HNDs) with nanotubes (NTs) on the surface (Ni SAs/FeN NPs@NC-HNDs-NTs).
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China.
The electroconversion of CO into ethylene (CH) offers a promising solution to environmental and energy challenges. Crown ether (CE) modification significantly enhances the CH selectivity of copper-based MOFs, improving CH faradaic efficiency (FE) in CuBTC, CuBDC, and CuBDC-NH by 3.1, 1.
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