Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Controlling Ni redox states by dynamic ligand exchange for electroreductive Csp3-Csp2 coupling.

ABSTRACT: Cross-electrophile coupling (XEC) reactions of aryl and alkyl electrophiles are appealing but limited to specific substrate classes. Here, we report electroreductive XEC of previously incompatible electrophiles including tertiary alkyl bromides, aryl chlorides, and aryl/vinyl triflates. Reactions rely on the merger of an electrochemically active complex that selectively reacts with alkyl bromides through 1e^- processes and an electrochemically inactive Ni⁰(phosphine) complex that selectively reacts with aryl electrophiles through 2e^- processes. Accessing Ni⁰(phosphine) intermediates is critical to the strategy but is often challenging. We uncover a previously unknown pathway for electrochemically generating these key complexes at mild potentials through a choreographed series of ligand-exchange reactions. The mild methodology is applied to the alkylation of a range of substrates including natural products and pharmaceuticals.

SUBMITTER: Hamby TB

PROVIDER: S-EPMC9260526 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

O-Benzyl Xanthate Esters under Ni/Photoredox Dual Catalysis: Selective Radical Generation and Csp3-Csp2 Cross-Coupling.

Project description:Alkyl xanthate esters are perhaps best known for their use in deoxygenation chemistry. However, their use in cross-coupling chemistry has not been productive, which is due, in part, to inadequate xanthate activation strategies. Herein, we report the use of O-benzyl xanthate esters, readily derived from alcohols, as radical pronucleophiles in Csp3-Csp2 cross-couplings under Ni/photoredox dual catalysis. Xanthate (C-O) cleavage is found to be reliant on photogenerated (sec-butyl) radical activators to form new carbon-centered radicals primed for nickel-catalyzed cross-couplings. Mechanistic experiments support the fact that the key radical components are formed independently, and relative rates are carefully orchestrated, such that no cross reactivity is observed.

| S-EPMC5460664 | biostudies-literature

Engaging sulfinate salts via Ni/photoredox dual catalysis enables facile Csp2 -SO2R coupling.

Project description:This report details the development and implementation of a strategy to construct aryl- and heteroaryl sulfones via Ni/photoredox dual catalysis. Using aryl sulfinate salts, the C-S bond can be forged at room temperature under base-free conditions. An array of aryl- and heteroaryl halides are compatible with this approach. The broad tolerance and mild nature of the described reaction could potentially be employed to prepare sulfones with biological relevance (e.g., in bioconjugation, drug substance synthesis, etc.) as demonstrated in the synthesis of drug-like compounds or their precursors. When paired with existing Ni/photoredox chemistry for Csp3 -Csp2 cross-coupling, an array of diverse sulfone scaffolds can be readily assembled from bifunctional electrophiles. A mechanistic manifold consistent with experimental and computational data is presented.

| S-EPMC5916223 | biostudies-literature

Electroreductive Olefin-Ketone Coupling.

Project description:A user-friendly approach is presented to sidestep the venerable Grignard addition to unactivated ketones to access tertiary alcohols by reversing the polarity of the disconnection. In this work a ketone instead acts as a nucleophile when adding to simple unactivated olefins to accomplish the same overall transformation. The scope of this coupling is broad as enabled using an electrochemical approach, and the reaction is scalable, chemoselective, and requires no precaution to exclude air or water. Multiple applications demonstrate the simplifying nature of the reaction on multistep synthesis, and mechanistic studies point to an intuitive mechanism reminiscent of other chemical reductants such as SmI2 (which cannot accomplish the same reaction).

| S-EPMC8353665 | biostudies-literature

Stereoselective Csp3 -Csp2 Cross-Couplings of Chiral Secondary Alkylzinc Reagents with Alkenyl and Aryl Halides.

Project description:We report palladium-catalyzed cross-coupling reactions of chiral secondary non-stabilized dialkylzinc reagents, prepared from readily available chiral secondary alkyl iodides, with alkenyl and aryl halides. This method provides ?-chiral alkenes and arenes with very high retention of configuration (dr up to 98:2) and satisfactory overall yields (up to 76?% for 3 reaction steps). The configurational stability of these chiral non-stabilized dialkylzinc reagents was determined and exceeded several hours at 25?°C. DFT calculations were performed to rationalize the stereoretention during the catalytic cycle. Furthermore, the cross-coupling reaction was applied in an efficient total synthesis of the sesquiterpenes (S)- and (R)-curcumene with control of the absolute stereochemistry.

| S-EPMC6973128 | biostudies-literature

Selective valorization of lignin to phenol by direct transformation of Csp2-Csp3 and C-O bonds.

Project description:Phenol is an important commodity chemical in the industry, which is currently produced using fossil feedstocks. Here, we report a strategy to produce phenol from lignin by directly deconstructing Csp2-Csp3 and C-O bonds under mild conditions. It was found that zeolite catalyst could efficiently catalyze both the direct Csp2-Csp3 bond breakage to remove propyl structure and aliphatic β carbon-oxygen (Cβ-O) bond hydrolysis to form OH group on the aromatic ring. The yield of phenol could reach 10.9 weight % with a selectivity of 91.8%. In this unique route, water was the only reactant besides lignin. A scale-up experiment showed that 4.1 g of pure phenol could be obtained from 50.0 g of lignin. The reaction pathway was proposed by a combination of control experiments and density functional theory studies. This work opens the way for producing phenol from lignin by direct transformation of Csp2-Csp3 and C-O bonds in lignin.

| S-EPMC7673717 | biostudies-literature

Practical Ni-Catalyzed Aryl-Alkyl Cross-Coupling of Secondary Redox-Active Esters.

Project description:A new transformation is presented that enables chemists to couple simple alkyl carboxylic acids with aryl zinc reagents under Ni-catalysis. The success of this reaction hinges on the unique use of redox-active esters that allow one to employ such derivatives as alkyl halides surrogates. The chemistry exhibits broad substrate scope and features a high degree of practicality. The simple procedure and extremely inexpensive nature of both the substrates and pre-catalyst (NiCl2·6H2O, ca. $9.5/mol) bode well for the immediate widespread adoption of this method.

| S-EPMC4768290 | biostudies-literature

Rapid Room-Temperature, Chemoselective Csp2 -Csp2 Coupling of Poly(pseudo)halogenated Arenes Enabled by Palladium(I) Catalysis in Air.

Project description:While chemoselectivities in Pd0 -catalyzed coupling reactions are frequently non-intuitive and a result of a complex interplay of ligand/catalyst, substrate, and reaction conditions, we herein report a general method based on PdI that allows for an a priori predictable chemoselective Csp2 -Csp2 coupling at C-Br in preference to C-OTf and C-Cl bonds, regardless of the electronic or steric bias of the substrate. The C-C bond formations are extremely rapid (<5 min at RT) and are catalyzed by an air- and moisture-stable PdI dimer under open-flask conditions.

| S-EPMC5299498 | biostudies-literature

Enantioselective Electroreductive Coupling of Alkenyl and Benzyl Halides via Nickel Catalysis.

Project description:An electrochemically-driven enantioselective nickel-catalyzed reductive cross-coupling of alkenyl bromides and benzyl chlorides is reported. The reaction forms products bearing allylic stereogenic centers with good enantioselectivity under mild conditions in an undivided cell. Electrochemical activation and turnover of the catalyst mitigate issues posed by metal powder reductants. This report demonstrates that enantioselective Ni-catalyzed cross-electrophile couplings can be driven electrochemically.

| S-EPMC7190267 | biostudies-literature

Palladium-Catalyzed Enantioselective Csp3-Csp3 Cross-Coupling for the Synthesis of (Poly)fluorinated Chiral Building Blocks.

Project description:A general method for the enantioselective synthesis of carbo- and heterocyclic carbonyl compounds bearing fluorinated α-tetrasubstituted stereocenters using palladium-catalyzed decarboxylative allylic alkylation is described. The stereoselective Csp3-Csp3 cross-coupling reaction delivers five- and six-membered ketone and lactam products bearing (poly)fluorinated tetrasubstituted chiral centers in high yields and enantioselectivities. These fluorinated, stereochemically rich building blocks hold potential value in medicinal chemistry and are prepared using an orthogonal and enantioselective approach into such chiral moieties compared to traditional approaches, often without the use of electrophilic fluorinating reagents.

| S-EPMC6192028 | biostudies-other

Exchange coupling and single molecule magnetism in redox-active tetraoxolene-bridged dilanthanide complexes.

Project description:Tetraoxolene radical-bridged lanthanide SMM systems were prepared for the first time by reduction of the respective neutral compounds. Magnetic measurements reveal the profound influence of the radical center on magnetic behavior. Strong magnetic couplings are revealed in the radical species, which switch on SMM behavior under zero applied field for DyIII and TbIII compounds. HFEPR spectra unravel the contributions of the magnetic coupling and the magnetic anisotropy. For GdIII this results in much more accurate magnetic coupling parameters with respect to bulk magnetic measurements.

| S-EPMC5885778 | 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