Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Alumination of aryl methyl ethers: switching between sp2 and sp3 C-O bond functionalisation with Pd-catalysis.

ABSTRACT: The reaction of [{(ArNCMe)2CH}Al] (Ar = 2,6-di-iso-propylphenyl) with aryl methyl ethers proceeded with alumination of the sp3 C-O bond. The selectivity of this reaction could be switched by inclusion of a catalyst. In the presence of [Pd(PCy3)2], chemoselective sp2 C-O bond functionalisation was observed. Kinetic isotope experiments and DFT calculations support a catalytic pathway involving the ligand-assisted oxidative addition of the sp2 C-O bond to a Pd-Al intermetallic complex.

SUBMITTER: Brown RK

PROVIDER: S-EPMC8567294 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Highly selective α-aryloxyalkyl C-H functionalisation of aryl alkyl ethers.

Project description:We report highly selective photocatalytic functionalisations of alkyl groups in aryl alkyl ethers with a range of electron-poor alkenes using an acridinium catalyst with a phosphate base and irradiation with visible light (456 nm or 390 nm). Experiments indicate that the reaction operates via direct single-electron oxidation of the arene substrate ArOCHRR' to its radical cation by the excited state organic photocatalyst; this is followed by deprotonation of the ArOC-H in the radical cation to yield the radical ArOC˙RR'. This radical then attacks the electrophile to form an intermediate alkyl radical that is reduced to complete the photocatalytic cycle. The oxidation step is selective for activated arenes (ArOR) over their non-activated counterparts and the subsequent deprotonation of the methoxy group affords the α-aryloxyalkyl radical that leads to a wide range of functionalised products in good to excellent yield.

| S-EPMC9645420 | biostudies-literature

Pd(II)-Catalyzed Cross-Coupling of C(sp2 )-H Bonds and Alkyl-, Aryl- and Vinyl-Boron Reagents via Pd(II)/Pd(0) Catalysis.

Project description:Pd(II)-catalyzed cross-coupling of ortho-C-H bonds in benzoic acid and phenylacetic acid amides with alkyl-, aryl- and vinyl-boron reagents have been achieved via Pd(II)/Pd(0) catalysis, demonstrating the unprecedented versatility of C-H activation reactions.

| S-EPMC3638876 | biostudies-literature

Iron-Catalyzed C(sp2)-C(sp3) Cross-Coupling of Aryl Chlorobenzoates with Alkyl Grignard Reagents.

Project description:Aryl benzoates are compounds of high importance in organic synthesis. Herein, we report the iron-catalyzed C(sp2)-C(sp3) Kumada cross-coupling of aryl chlorobenzoates with alkyl Grignard reagents. The method is characterized by the use of environmentally benign and sustainable iron salts for cross-coupling in the catalytic system, employing benign urea ligands in the place of reprotoxic NMP (NMP = N-methyl-2-pyrrolidone). It is notable that high selectivity for the cross-coupling is achieved in the presence of hydrolytically-labile and prone to nucleophilic addition phenolic ester C(acyl)-O bonds. The reaction provides access to alkyl-functionalized aryl benzoates. The examination of various O-coordinating ligands demonstrates the high activity of urea ligands in promoting the cross-coupling versus nucleophilic addition to the ester C(acyl)-O bond. The method showcases the functional group tolerance of iron-catalyzed Kumada cross-couplings.

| S-EPMC6983197 | biostudies-literature

Asymmetric synthesis of multifunctional aryl allyl ethers by nucleophilic catalysis.

Project description:Asymmetric allylic substitution of Morita-Baylis-Hillman (MBH) carbonates with less-nucleophilic phenols mediated by nucleophilic amine catalysis was successfully developed. A variety of substituted aryl allyl ethers were afforded with moderate to high yields with excellent enantioselectivities. The chiral MBH alcohol could be easily accessed from the corresponding aryl allyl ether.

| S-EPMC9063376 | biostudies-literature

Enantioselective ?-C(sp3)-H Activation of Alkyl Amines via Pd(II)/Pd(0) Catalysis.

Project description:Pd(II)-catalyzed enantioselective ?-C(sp3)-H cross-coupling of alkyl amines via desymmetrization and kinetic resolution has been realized for the first time using chiral acetyl-protected aminomethyl oxazoline ligands (APAO). A diverse range of aryl- and vinyl-boron reagents can be used as coupling partners. The chiral ?-arylated alkylamine products are further transformed into chiral 2-substituted 1,2,3,4-tetra-hydroquinolines and spiro-pyrrolidines as important structural motifs in natural products and biologically active molecules.

| S-EPMC5927623 | biostudies-literature

Ligand-enabled methylene C(sp3)-H bond activation with a Pd(II) catalyst.

Project description:Pd(II) insertion into β-methylene C(sp(3))-H bonds was enabled by a mutually repulsive and electron-rich quinoline ligand. Ligand tuning led to the development of a method that allows for installation of an aryl group on a range of acyclic and cyclic amides containing β-methylene C(sp(3))-H bonds.

| S-EPMC3500088 | biostudies-literature

Modular synthesis of dihydro-isoquinolines: palladium-catalyzed sequential C(sp2)-H and C(sp3)-H bond activation.

Project description:An efficient synthesis of dihydro-isoquinolines via a Pd-catalyzed double C-H bond [a C(sp2)-H and a C(sp3)-H bond] activation/annulation (CHAA) reaction is presented. This methodology features a short reaction time, high atom economy (loss of H2O only) and the formation of a sterically less favoured tertiary C-N bond. This fast (30 min) and environmentally benign radical C-H activation approach has demonstrated the potential direction for the future design/development of fast and efficient C-H direct functionalization processes.

| S-EPMC5950195 | biostudies-other

Stereoselective alkoxycarbonylation of unactivated C(sp3)-H bonds with alkyl chloroformates via Pd(II)/Pd(IV) catalysis.

Project description:Several examples on Pd-catalysed carbonylation of methyl C(sp3)-H bonds with gaseous CO via Pd(II)/Pd(0) catalysis have been reported. However, methylene C(sp3)-H carbonylation remains a great challenge, largely due to the lack of reactivity of C-H bonds and the difficulty in CO migratory insertion. Herein, we report the stereoselective alkoxycarbonylation of both methyl and methylene C(sp3)-H bonds with alkyl chloroformates through a Pd(II)/Pd(IV) catalytic cycle. A broad range of aliphatic carboxamides and alkyl chloroformates are compatible with this protocol. In addition, this process is scalable and the directing group could be easily removed under mild conditions with complete retention of configuration.

| S-EPMC5052708 | biostudies-literature

Ligand-enabled cross-coupling of C(sp3)-H bonds with arylboron reagents via Pd(II)/Pd(0) catalysis.

Project description:There have been numerous developments in C-H activation reactions in the past decade. Attracted by the ability to functionalize molecules directly at ostensibly unreactive C-H bonds, chemists have discovered reaction conditions that enable reactions of C(sp(2))-H and C(sp(3))-H bonds with a variety of coupling partners. Despite these advances, the development of suitable ligands that enable catalytic C(sp(3))-H bond functionalization remains a significant challenge. Herein we report the discovery of a mono-N-protected amino acid ligand that enables Pd(II)-catalysed coupling of ?-C(sp(3))-H bonds in triflyl-protected amines with arylboron reagents. Remarkably, no background reaction was observed in the absence of ligand. A variety of amine substrates and arylboron reagents were cross-coupled using this method. Arylation of optically active substrates derived from amino acids also provides a potential route for preparing non-proteinogenic amino acids.

| S-EPMC4077182 | biostudies-literature

Aryl Silyl Ethers Enable Preferential Ar-O bond Cleavage in Reductive Generation of Aryllithium Species.

Project description:Two-electron transfer to haloarenes constitutes one of the most reliable synthetic methodologies for the generation of aryllithiums. In addition to the conventional halides, readily available aryl ethers can function as potent substrates. However, it is known that the reductive cleavage of alkoxides is plagued by insufficient selectivity concerning the cleaving bond adjacent to the ether oxygen, resulting in decreased reliability of these alkoxyarene substrates. In the present study, we discovered that naphthalenes bearing readily installable tert-butyldimethylsilyl ethers undergo two-electron reduction with lithium metal, resulting in lithiation at the position of the original siloxy group. DFT calculations elucidated the rationale for the change in selectivity upon incorporation of the siloxy group. Our results underscore the practical utility of a siloxy group as a leaving group for reductive transformations involving electron transfer.

| S-EPMC11350566 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data