Browse
Submit Data
Databases
API
Help

Dataset Information

53 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Rh(i)- and Rh(ii)-catalyzed C-H alkylation of benzylamines with alkenes and its application in flow chemistry.

ABSTRACT: The Rh-catalyzed C-H alkylation of benzylamines with alkenes using a picolinamide derivative as a directing group is reported. Both Rh(i) and Rh(ii) complexes can be used as active catalysts for this transformation. In addition, a flow set up was designed to successfully mimic this process under flow conditions. Several examples are presented under flow conditions and it was confirmed that a flow process is advantageous over a batch process. Deuterium labelling experiments were performed to elucidate the mechanism of the reaction, and the results indicated a possible carbene mechanism for this C-H alkylation process.

SUBMITTER: Das A

PROVIDER: S-EPMC8179371 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Rh(i)- and Rh(ii)-catalyzed C-H alkylation of benzylamines with alkenes and its application in flow chemistry.

Das Amrita A Chatani Naoto N

Chemical science 20210104 9

The Rh-catalyzed C-H alkylation of benzylamines with alkenes using a picolinamide derivative as a directing group is reported. Both Rh(i) and Rh(ii) complexes can be used as active catalysts for this transformation. In addition, a flow set up was designed to successfully mimic this process under flow conditions. Several examples are presented under flow conditions and it was confirmed that a flow process is advantageous over a batch process. Deuterium labelling experiments were performed to eluc ...[more]

PMID: 34164088

Similar Datasets

Rh(II)-Catalyzed Alkynylcyclopropanation of Alkenes by Decarbenation of Alkynylcycloheptatrienes.

Project description:Alkynylcyclopropanes have found promising applications in both organic synthesis and medicinal chemistry but remain rather underexplored due to the challenges associated with their preparation. We describe a convenient two-step methodology for the alkynylcyclopropanation of alkenes, based on the rhodium(II)-catalyzed decarbenation of 7-alkynyl cycloheptatrienes. The catalytic system employed circumvents a fundamental problem associated with these substrates, which usually evolve via 6-endo-dig cyclization or ring-contraction pathways under metal catalysis. This unique performance unlocks a rapid access to a diverse library of alkynylcyclopropanes (including derivatives of complex drug-like molecules), versatile intermediates that previously required much lengthier synthetic approaches. Combining experiments and DFT calculations, the complete mechanistic picture for the divergent reactivity of alkynylcycloheptatrienes under metal catalysis has been unveiled, rationalizing the unique selectivity displayed by rhodium(II) complexes.

| S-EPMC8299462 | biostudies-literature

Rh(ii)-catalyzed branch-selective C-H alkylation of aryl sulfonamides with vinylsilanes.

Project description:Rhodium(ii)-catalyzed unusual branch-selective ortho-C-H alkylation of aryl sulfonamides with vinylsilanes was achieved using an 8-aminoquinoline directing group. Notably, the para-substituted aryl sulfonamides gave mono-(branched)alkylated products exclusively without the formation of any double C-H alkylated byproducts. The results of deuterium labeling experiments suggest that both hydrometalation and carbometalation pathways are involved in this conversion.

| S-EPMC7069504 | biostudies-literature

Rh-Catalyzed Enantioselective Single-Carbon Insertion of Alkenes.

Project description:The interest in the discovery and development of skeletal editing processes that selectively insert, exchange, or delete an atom in organic molecules has significantly increased over the last few years. However, processes of this class that proceed through the creation of a chiral center with high asymmetric induction have been largely unexplored. Herein, we report an enantioselective single-carbon insertion in aryl- and alkyl-substituted alkenes mediated by a catalytically generated chiral Rh-carbynoid and phosphate nucleophiles that produce enantioenriched allylic phosphates (enantiomeric ratio (e.r.) = 89.5:10.5-99.5:0.5). The key to the process was a diastereo- and enantioselective cyclopropanation of the alkene with a chiral Rh-carbynoid and the formation of a transient cyclopropyl-I(III) intermediate. The addition of the phosphate nucleophile provided a cyclopropyl-I(III)-phosphate intermediate that undergoes disrotatory ring opening following the Woodward-Hoffmann-DePuy rules. This process led to a chiral intimate allyl cation-phosphate pair that evolved with excellent enantioretention. The evidence of an SN1-like SNi mechanism is provided by linear free-energy relationship studies, kinetic isotope effects, X-ray crystallography, and control experiments. We demonstrated the utility of the enantioenriched allylic phosphates in late-stage N-H allylations of natural products and drug molecules and in cross-coupling reactions that occurred with excellent enantiospecificity.

| S-EPMC11311232 | biostudies-literature

Site-Selective and Stereoselective <i>O</i>-Alkylation of Glycosides by Rh(II)-Catalyzed Carbenoid Insertion.

Project description:Carbohydrates are synthetically challenging molecules with vital biological roles in all living systems. Selective synthesis and functionalization of carbohydrates provide tremendous opportunities to improve our understanding on the biological functions of this fundamentally important class of molecules. However, selective functionalization of seemingly identical hydroxyl groups in carbohydrates remains a long-standing challenge in chemical synthesis. We herein describe a practical and predictable method for the site-selective and stereoselective alkylation of carbohydrate hydroxyl groups via Rh(II)-catalyzed insertion of metal carbenoid intermediates. This represents one of the mildest alkylation methods for the systematic modification of carbohydrates. Density functional theory (DFT) calculations suggest that the site selectivity is determined in the Rh(II)-carbenoid insertion step, which prefers insertion into hydroxyl groups with an adjacent axial substituent. The subsequent intramolecular enolate protonation determines the unexpected high stereoselectivity. The most prevalent trans-1,2-diols in various pyranoses can be systematically and predictably differentiated based on the model derived from DFT calculations. We also demonstrated that the selective O-alkylation method could significantly improve the efficiency and stereoselectivity of glycosylation reactions. The alkyl groups introduced to carbohydrates by OH insertion reaction can serve as functional groups, protecting groups, and directing groups.

| S-EPMC6920555 | biostudies-literature

Rh(III)-catalyzed oxidative coupling of unactivated alkenes via C-H activation.

Project description:Oxime directed aromatic C-H bond activation and oxidative coupling to alkenes is reported using a cationic Rh(III) catalyst. Significantly, the method can be used to oxidatively couple unactivated, aliphatic alkenes.

| S-EPMC3031716 | biostudies-literature

Kinetic Resolution of Benzylamines via Palladium(II)-Catalyzed C-H Cross-Coupling.

Project description:A Pd(II)-catalyzed enantioselective C-H cross-coupling of benzylamines via kinetic resolution has been achieved using chiral mono-N-protected α-amino-O-methylhydroxamic acid (MPAHA) ligands. Both chiral benzylamines and ortho-arylated benzylamines are obtained in high enantiomeric purity. The use of a readily removable nosyl (Ns) protected amino group as the directing group is a crucial practical advantage. Moreover, the ortho-arylated benzylamine products could be further transformed into chiral 6-substituted 5,6-dihydrophenanthridines as important structural motifs in natural products and bioactive molecules.

| S-EPMC5516893 | biostudies-literature

Facile Pd(II)- and Ni(II)-catalyzed isomerization of terminal alkenes into 2-alkenes.

Project description:Mono- and 2,2'-disubstituted terminal alkenes can be isomerized into the more stable internal (Z)- and (E)-alkenes by treating them with catalytic amounts of [(allyl)PdCl](2) or [(allyl)NiBr](2), a triarylphosphine, and silver triflate at room temperature. The isomeric ratio (E:Z) depends on the alkenes, the E-isomer being the major one. The reaction is tolerant to a wide variety of functional groups including other reactive olefins. Unlike the more reactive Ir catalysts, monosubstituted alkenes give almost exclusively the 2-alkenes. Direct comparison to two of the best-known catalysts for this process {[Ir(PCy(3))(3)](+)[BPh(4)](-) and Grubbs generation II metathesis catalyst} is also described.

| S-EPMC2715430 | biostudies-literature

Rh(I)-catalyzed alkylation of quinolines and pyridines via C-H bond activation.

Project description: Not available

| S-EPMC2518126 | biostudies-literature

Rh(iii)-catalyzed tandem annulative redox-neutral arylation/amidation of aromatic tethered alkenes.

Project description:Transition-metal-catalyzed directed C-H functionalization has emerged as a powerful and straightforward tool to construct C-C bonds and C-N bonds. Among these processes, the intramolecular annulative alkene hydroarylation reaction has received much attention because this intramolecular annulation can produce more complex and high value-added structural motifs found in numerous natural products and bioactive molecules. Despite remarkable progress, these annulative protocols developed to date remain limited to hydroarylation and functionalization of one side of alkenes, thus largely limiting the structural diversity and complexity. Herein, we developed a rhodium(iii)-catalyzed tandem annulative arylation/amidation reaction of aromatic tethered alkenes to deliver a variety of 2,3-dihydro-3-benzofuranmethanamine derivatives bearing an all-carbon quaternary stereo center by employing 3-substituted 1,4,2-dioxazol-5-ones as an amidating reagent to capture the transient C(sp3)-Rh intermediate. Notably, by simply changing the directing group, a second, unsymmetrical ortho C-H amidation/annulation can be achieved to provide tricyclic dihydrofuro[3,2-f]quinazolinones in good yields.

| S-EPMC8162841 | biostudies-literature

Phosphine Oxide-Promoted Rh(I)-Catalyzed C-H Cyclization of Benzimidazoles with Alkenes.

Project description:Ligands play a critical role in promoting transition-metal-catalyzed C-H activation reactions. However, owing to high sensitivity of the reactivity of C-H activation to metal catalysts, the development of effective ligands has been a formidable challenge in the field. Rh(I)-catalyzed C-H cyclization of benzimidazoles with alkenes has been faced with low reactivity, often requiring very harsh conditions. To address this challenge, a phosphine oxide-enabled Rh(I)-Al bimetallic catalyst was developed for the reaction, significantly promoting the reactivity and allowing the reaction to run at 120 °C with up to 97% yield.

| S-EPMC9864171 | 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