A palladium-catalyzed domino Heck/intermolecular direct hetero arylation sequence of unactivated alkenes was developed, providing 1,2,3-triazole containing bisheterocycles bearing all-carbon quaternary centers with yields of 25-90%. The protocol was extended to 1,3,4-oxadiazoles as well. The installed triazole was further exploited for late-stage functionalizations, and the mechanistic studies indicate the involvement of C-H activation.
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http://dx.doi.org/10.1039/d1ob00195g | DOI Listing |
Chem Commun (Camb)
December 2024
School of Chemistry, University College Dublin, Science Centre South, Dublin 4, Ireland.
We report a continuous flow approach generating bicyclic cyclobutanes from unactivated alkenes in a metal-free manner that is inspired by the Kochi-Salomon reaction. A filtered Hg-lamp in combination with a simple flow set-up and acetone as UV light-absorbing co-solvent are crucial for this method thus showcasing attractive features for further exploitations.
View Article and Find Full Text PDFJ Org Chem
December 2024
School of Chemistry and Chemical Engineering, Kunming University, Kunming, Yunnan 650214, P. R. China.
We report an electrophotocatalytic process that enables the thiocyanation and sulfonylation/cyclization of alkenes. It is applicable to a wide range of unactivated alkenes, using the inexpensive photocatalyst 2,4,6-triphenylpyrylium tetrafluoroborate (TPPT) to produce a diverse array of heterocycles containing sulfonyl and thiocyano groups with good functional group tolerance. The protocol operates under mild, chemical oxidant- and transition-metal-free, with a broad scope of substrates.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Tsinghua University, Department of Chemistry, 1 Tsinghua Yuan, 100084, Beijing, CHINA.
Catalytic regio- and enantioselective hydroamination of less activated internal alkenes presents a challenge to synthetic chemists due to their low reactivity and the difficulty in simultaneously controlling regio- and enantioselectivities. Here, we report an iridium-catalyzed enantioselective hydroamination of internal alkenes directed by an amide. The amide group on the alkene effectively directs the catalyst to overcome the low reactivity and control the regioselectivity and the enantiotopic face selection.
View Article and Find Full Text PDFOrg Lett
December 2024
Key Laboratory of Bio-Based Material Science and Technology, Ministry of Education, College of Material Science and Engineering, Northeast Forestry University, Harbin 150040, People's Republic of China.
A visible-light-induced method for the hydrodichloromethylation of unactivated alkenes using chloroform (CHCl) was developed, employing pyridine·BH as the halogen atom transfer (XAT) reagent. The strategy showed a broad functional group tolerance, and 29 examples of unactivated alkenes, including complex natural products or drug derivatives, have been established with good yields. Mechanistic studies indicated that CHCl serves as both the source of a dichloromethyl radical and a hydrogen atom transfer (HAT) reagent, and the borane short-chain reaction process was involved in this system.
View Article and Find Full Text PDFChem
October 2024
Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States.
Arylethylamines represent a privileged scaffold in pharmaceutical compounds and form the backbone of many medical drugs, including those used for treating neurological diseases and pain. Their biomedical significance has inspired new synthetic methods that rely on transition metal-catalyzed aminoarylation reaction to an alkene, often in conjunction with a photoredox catalyst or a photosensitizer, and guided by a directing or stabilizing group. Here, we introduce a simple and effective method for azidoarylation of unactivated alkenes under transition metal-free conditions.
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