Low-valent manganese-catalyzed C-H alkylation of pyridine derivatives with both primary and challenging secondary alkyl halides was established by amide assistance. The strategy provided expedient access to alkylated pyridines with wide functional group tolerance and ample scope through weak chelation. Mechanistic studies provided strong support for a rate-determining C-H activation and a SET-type C-X scission.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.orglett.8b03924 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Facile and Regioselective Deuteration of C2-Alkylated Imidazolium Salts in the Presence of Cesium Carbonate.
Chemistry
December 2024
Université de Liège: Universite de Liege, Laboratory of Organometallic Chemistry and Homogeneous Catalysis, Institut de chimie B6a, Sart-Tilman, 4000, Liege, BELGIUM.
Thirteen imidazolium iodides bearing benzyl, mesityl, or 2,6-diiso-propyl-phenyl substituents on their nitrogen atoms, and C1 to C4 alkyl chains on their C2 carbon atom were readily deuterated with D2O as a cheap and non-toxic deuterium source in the presence of Cs2CO3, a weak, innocuous, inorganic base. The isotopic exchange proceeded quickly and efficiently under mild, aerobic conditions to afford a range of aNHC and NHO precursors regioselectively labeled on their C2α exocyclic position and/or C4=C5 heterocyclic backbone. A "carbene-free" mechanism was postulated, in which the carbonate anion acts as a catalyst to activate an exocyclic, acidic C-H bond and ease a deuterium transfer from D2O to the imidazolium salt in a concerted fashion.
View Article and Find Full Text PDFPhosphite mediated molecular editing switch to -C-H alkylation of isoquinolines: emergence of a distinct photochemical [1,3] N to C rearrangement.
Chem Sci
December 2024
Organic Chemistry Division, CSIR-National Chemical Laboratory (CSIR-NCL) Pune 411 008 India
The isoquinoline core is present in one of the largest subsets of bioactive natural products. The multifunctional isoquinoline core exerts diverse bioactivity, resulting in the development of numerous isoquinoline-based drugs and molecules that are currently under clinical trials. We developed a new approach for phosphite-mediated [1,2] alkyl migration for an overall -C-H alkylation -alkylation of isoquinoline.
View Article and Find Full Text PDFHeteroaryl-Directed Iridium-Catalyzed Enantioselective C-H Alkenylations of Secondary Alcohols.
J Am Chem Soc
December 2024
Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, United Kingdom.
Under iridium-catalyzed conditions, 2-aza-aryl-substituted secondary alcohols undergo C(sp)-H addition reactions to alkynes to provide alkenylated tertiary alcohols. The processes occur with very high regio- and enantioselectivity. An analogous addition to styrene is shown to provide a prototype C(sp)-H alkylation process.
View Article and Find Full Text PDFPhotocatalytic Multiple Deuteration of Polyethylene Glycol Derivatives using Deuterium Oxide.
Chemistry
December 2024
Osaka University, Graduate School of Pharmaceutical Sciences, 1-6, Yamada-oka, 565-0871, Osaka, JAPAN.
Deuterated molecules are of growing interest because of the specific characteristics of deuterium, such as stronger C-D bonds being stronger than C-H bonds. Polyethylene glycols (PEGs) are widely utilized in scientific fields (e.g.
View Article and Find Full Text PDFC-H Functionalization of Imidazo[1,5-]pyridines: A Metal-Free Approach for Methylene Insertion to Access C(sp)-C(sp)-H-C(sp) Bond Formation.
ACS Omega
December 2024
Natural Products and Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Jammu 180001, India.
Formaldehyde has been used as a solvent and a source of carbon to insert a methylene group for bridging two imidazo[1,5-]pyridine molecules without using any metal catalysis. This strategy has been extended on other alkyl-, aryl-, and heteroaryl aldehydes as well. This C(sp)-C(sp)-H-C(sp) bond forming reaction proceeds via C(sp)H functionalization of imidazo[1,5-]pyridine and was applied on a wide range of substrates offering moderate to good yields of methylene-bridged/inserted bis-imidazo[1,5-]pyridines.
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!