N-alkylation of 5-hydroxynicotinic acid esters with electrophiles containing diene functionality produces salts that undergo intramolecular (4+3) cycloaddition reactions upon heating in the presence of base. Initial studies used a three-carbon tether to join the pyridinium ion and diene, revealing some aspects of the inherent selectivity of the reaction with such substrates. Much more challenging was the synthesis of related species possessing only a two-carbon tether. Nevertheless, the cycloaddition of such compounds was successful, leading directly to the ABC ring system of the alkaloid daphnicyclidin A.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/chem.202200370 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Benzo[1,2-b:6,5-b']dithiophene-4,5-diamine: A New Fluorescent Probe for the High-Sensitivity and Real-Time Visual Monitoring of Phosgene.
Sensors (Basel)
January 2025
State Key Laboratory of Marine Resource Utilization in South China Sea, School of Chemistry and Chemical Engineering, Hainan University, Haikou 570228, China.
The detection of highly toxic chemicals such as phosgene is crucial for addressing the severe threats to human health and public safety posed by terrorist attacks and industrial mishaps. However, timely and precise monitoring of phosgene at a low cost remains a significant challenge. This work is the first to report a novel fluorescent system based on the Intramolecular Charge Transfer (ICT) effect, which can rapidly detect phosgene in both solution and gas phases with high sensitivity by integrating a benzo[1,2-b:6,5-b']dithiophene-4,5-diamine (BDTA) probe.
View Article and Find Full Text PDFBuilding Three-Dimensional Complexity by Intramolecular 2-Aminoallyl Cation-Diene (4+3) Cycloaddition.
Angew Chem Int Ed Engl
January 2025
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, P. R. China.
Reliable methods for rapidly constructing C(sp)-rich three-dimensional polycycles are in high demand for organic synthesis and medicinal chemistry. Although there are various mature systems for synthesizing five- or six-membered polycycles, a catalytic platform for accessing diverse cycloheptanoid-containing polycyclic scaffolds is lacking. Herein, we describe a method for copper-catalyzed intramolecular 2-aminoallyl cation-diene (4+3) cycloaddition reactions.
View Article and Find Full Text PDFSecupyritines A-C, Three Natural Propellane Securinega Alkaloids: Structure Elucidation and Total Synthesis Based on Biogenetic Building Blocks.
Angew Chem Int Ed Engl
January 2025
State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 510632, China.
Secupyritines A-C are unique polycyclic Securinega alkaloids isolated from medicinal plant Flueggea suffruticosa. They feature a distinctive 6/6/6/5/6 fused pentacyclic ring system with a highly strained 2-oxa-6-aza[4.4.
View Article and Find Full Text PDFSynthetic Study toward Daphnimacropodines.
Org Lett
December 2024
Department of Chemistry and Shenzhen Grubbs Institute and Guangdong Provincial Key Laboratory of Catalysis and Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China.
Daphnimacropodines A-C are members of a small but structurally distinct subfamily of alkaloids. Their congested polycyclic skeletons, and two vicinal quaternary stereocenters, present significant synthetic challenges. This paper describes two stereoselective approaches to constructing the tricyclic core structures of daphnimacropodines, achieved through a straightforward Rh-catalyzed [4 + 3] cycloaddition using simple building blocks.
View Article and Find Full Text PDFA Facile and Efficient Synthesis of BODIPY-Based Fluorescent Probes for Selective Detection of Hydrazine.
Chem Asian J
November 2024
Department of Chemistry, Birla Institute of Technology and Science, Pilani Campus, Pilani, 333 031, India.
A facile and ratiometric BODIPY-based fluorescent probe 4 was developed for the selective detection of hydrazine in solution phase. The BODIPY-based fluorophores 3 and 4 were easily prepared in high yields from the L-proline catalyzed reaction between α/β-formyl BODIPY 1 a/1 b and 3-cyanoacetylindole 2. Use of easily accessible substrates, benign solvent, catalytic amount of L-proline and high product yields are the advantageous features of the developed protocol.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!