Palladium(0)/monophosphine complexes catalyze anti-selective alkylative, arylative, and alkynylative cyclizations of alkynyl electrophiles with organometallic reagents. The remarkable anti-selectivity results from novel oxidative addition, that is, the nucleophilic attack of electron-rich palladium(0) on the electrophile across the alkyne followed by transmetalation and reductive elimination ("anti-Wacker"-type cyclization). With regard to 5-alkynals, triphenylphosphine (PPh )-ligated palladium(0) catalyzes the cyclization of terminal alkynes and conjugated alkenyl- or alkynyl-substituted ones to afford 2-cyclohexen-1-ol and 2-alkylidene-cyclopentanol derivatives, respectively. For 6-alkyl- or 6-aryl-5-alkynals, the cyclization does not proceed with the palladium/PPh catalyst; however, it does proceed with palladium/tricyclohexylphosphine (PCy ), to yield the former products predominantly. Remarkably, the latter catalyst completely switches the regioselectivity in the cyclization of the conjugated diyne-aldehydes. Notably, palladium/PPh -catalyzed cyclizations also proceed with other organometallics or even without them.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10108115 | PMC |
| http://dx.doi.org/10.1002/chem.202203068 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Palladium-Catalyzed Solvent-Controlled Divergent C2/C5 Site-Selective Alkynylation of Pyrrole Derivatives.
J Org Chem
January 2025
Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning, Guangxi 530004, China.
Among the known aromatic -heterocycles, pyrroles are significant and versatile privileged components in pharmacologically relevant molecules. Herein, we demonstrate a protocol for the selective construction of alkynylated pyrroles in a diversity-oriented fashion through divergent C2/C5 site-selective alkynylation of pyrrole derivatives by employing a palladium catalyst with two different solvent systems. In the presence of 1,4-dioxane, the C2-alkynylation process via chelation-assisted palladation is favored.
View Article and Find Full Text PDFIntermediate Control: Unlocking Hitherto Unknown Reactivity and Selectivity in N-Conjugated Allenes and Alkynes.
Acc Chem Res
January 2025
Department of Chemistry and Chemistry Institution for Functional Materials, Pusan National University, Busan 46241, Republic of Korea.
ConspectusControlling selectivity through manipulation of reaction intermediates remains one of the most enduring challenges in organic chemistry, providing novel solutions for selective C-C π-bond functionalization. This approach, guided by activation principles, provides an effective method for selective functional group installation, enabling direct synthesis of organic molecules that are inaccessible through conventional pathways. In particular, the selective functionalization of N-conjugated allenes and alkynes has emerged as a promising research focus, driven by advances in controlling reactive intermediates and activation strategies.
View Article and Find Full Text PDFBoryl radical-mediated halogen-atom transfer (XAT) enables the Sonogashira-like alkynylation of alkyl halides.
Chem Sci
October 2024
Institute of Organic Chemistry, RWTH Aachen University Landoltweg 1 Aachen 52056 Germany
Alkynes are a crucial class of materials with application across the wide range of chemical disciplines. The alkynylation of alkyl halides presents an ideal strategy for assembling these materials. Current methods rely on the intrinsic electrophilic nature of alkyl halides to couple with nucleophilic acetylenic systems, but these methods faces limitations in terms of applicability and generality.
View Article and Find Full Text PDFDiscovery of Trypanosoma brucei inhibitors enabled by a unified synthesis of diverse sulfonyl fluorides.
Commun Chem
October 2024
School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
Sets of electrophilic probes are generally prepared using a narrow toolkit of robust reactions, which tends to limit both their structural and functional diversity. A unified synthesis of skeletally-diverse sulfonyl fluorides was developed that relied upon photoredox-catalysed dehydrogenative couplings between hetaryl sulfonyl fluorides and hydrogen donor building blocks. A set of 32 diverse probes was prepared, and then screened against Trypanosoma brucei.
View Article and Find Full Text PDFSurface Functionalization of Gold Nanoparticles Using Alkyne Derivatives: Applications in Chemical Sensing.
ACS Appl Mater Interfaces
October 2024
Department of Chemistry, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 300044, Taiwan.
Article Synopsis
- Colloidal gold nanoparticles (AuNPs) are critical for chemical sensing and therapeutic applications, necessitating effective surface functionalization for stability in biological environments.
- Traditional methods use thiol groups for bonding, but these can be complex and not resilient to certain conditions, leading to the exploration of alkyne derivatives as a preferable alternative.
- The study shows that alkyne derivatives provide easier preparation, higher stability, and better conjugation efficiency, and highlights their effectiveness in detecting hydrogen peroxide and streptavidin proteins.
Want 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!