Browse
Submit Data
Databases
API
Help

Dataset Information

13 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Light-Mediated Formal Radical Deoxyfluorination of Tertiary Alcohols through Selective Single-Electron Oxidation with TEDA2+.

ABSTRACT: The synthesis of tertiary alkyl fluorides through a formal radical deoxyfluorination process is described herein. This light-mediated, catalyst-free methodology is fast and broadly applicable allowing for the preparation of C-F bonds from (hetero)benzylic, propargylic, and non-activated tertiary alcohol derivatives. Preliminary mechanistic studies support that the key step of the reaction is the single-electron oxidation of cesium oxalates-which are readily available from the corresponding tertiary alcohols-with in situ generated TEDA2+. (TEDA: N-(chloromethyl)triethylenediamine), a radical cation derived from Selectfluor®.

SUBMITTER: Aguilar Troyano FJ

PROVIDER: S-EPMC6899844 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Light-Mediated Formal Radical Deoxyfluorination of Tertiary Alcohols through Selective Single-Electron Oxidation with TEDA2+.

Aguilar Troyano Francisco José FJ Ballaschk Frederic F Jaschinski Marcel M Özkaya Yasemin Y Gómez-Suárez Adrián A

Chemistry (Weinheim an der Bergstrasse, Germany) 20191018 62

The synthesis of tertiary alkyl fluorides through a formal radical deoxyfluorination process is described herein. This light-mediated, catalyst-free methodology is fast and broadly applicable allowing for the preparation of C-F bonds from (hetero)benzylic, propargylic, and non-activated tertiary alcohol derivatives. Preliminary mechanistic studies support that the key step of the reaction is the single-electron oxidation of cesium oxalates-which are readily available from the corresponding terti ...[more]

PMID: 31452265

Similar Datasets

Late-stage deoxyfluorination of alcohols with PhenoFluor.

Project description:An operationally simple protocol for the selective deoxyfluorination of structurally complex alcohols is presented. Several fluorinated derivatives of natural products and pharmaceuticals have been prepared to showcase the potential of the method for late-stage diversification and its functional group compatibility. A series of simple guidelines for predicting the selectivity in substrates with multiple alcohols is given.

| S-EPMC3596866 | biostudies-literature

Selective Radical-Radical Cross-Couplings: Design of a Formal ?-Mannich Reaction.

Project description:A direct ?-coupling of cyclic ketones with imines has been accomplished via the synergistic combination of photoredox catalysis and organocatalysis. Transient ?-enaminyl radicals derived from ketones via enamine and oxidative photoredox catalysis readily combine with persistent ?-amino radicals in a highly selective hetero radical-radical coupling. This novel pathway to ?-aminoketones is predicated upon the use of DABCO as both a base and an electron transfer agent. This protocol also formally allows for the direct synthesis of ?-Mannich products via a chemoselective three-component coupling of aryl aldehydes, amines, and ketones.

| S-EPMC4629778 | biostudies-literature

Deoxyfluorination of alcohols with 3,3-difluoro-1,2-diarylcyclopropenes.

Project description:Aromatic cation activation is a useful strategy to promote deoxyfunctionalization; however, the deoxyfluorination of alcohols with cyclopropenium cation remains an unsolved problem due to the weak nucleophilicity of fluoride ion. Here we report the use of 3,3-difluoro-1,2-diarylcyclopropenes (CpFluors) as easily accessible and reactivity-tunable deoxyfluorination reagents. The electronic nature of CpFluors is critical for fluorination of monoalcohols via alkoxycyclopropenium cations, and CpFluors with electron-rich aryl substituents facilitate the transformation with high efficiency; however, selective monofluorination of 1,2- and 1,3-diols, which proceeds via cyclopropenone acetals, is less dependent on the electronic nature of CpFluors. Moreover, CpFluors are more sensitive to the electronic nature of alcohols than many other deoxyfluorination reagents, thus fluorination of longer diols can be achieved selectively at the relatively electron-rich position. This research not only unveils the first example of deoxyfluorination reagents that contain an all-carbon scaffold, but also sheds light on the divergent reactivity of cyclopropenium cation in deoxyfunctionalization of alcohols.

| S-EPMC5114535 | biostudies-literature

Oxidizable Ketones: Persistent Radical Cations from the Single-Electron Oxidation of 2,3-Diaminocyclopropenones.

Project description:Single electron oxidation of 2,3-diaminocyclopropenones is shown to give rise to stable diaminocyclopropenium oxyl (DACO) radical cations. Cyclic voltammetry reveals reversible oxidations in the range of +0.70-1.10?V (vs. SCE). Computational, EPR, and X-ray analysis support the view that the oxidized species is best described as a cyclopropenium ion with spin density located on the heteroatom substituents, including 23.5?% on oxygen. The metal-ligand behavior of the DACO radical is also described.

| S-EPMC6546530 | biostudies-literature

Selective deoxygenative alkylation of alcohols via photocatalytic domino radical fragmentations.

Project description:The delivery of alkyl radicals through photocatalytic deoxygenation of primary alcohols under mild conditions is a so far unmet challenge. In this report, we present a one-pot strategy for deoxygenative Giese reaction of alcohols with electron-deficient alkenes, by using xanthate salts as alcohol-activating groups for radical generation under visible-light photoredox conditions in the presence of triphenylphosphine. The convenient generation of xanthate salts and high reactivity of sequential C-S/C-O bond homolytic cleavage enable efficient deoxygenation of primary, secondary and tertiary alcohols with diverse functionality and structure to generate the corresponding alkyl radicals, including methyl radical. Moreover, chemoselective radical monodeoxygenation of diols is achieved via selective formation of xanthate salts.

| S-EPMC8433232 | biostudies-literature

Photoredox-catalyzed deoxyfluorination of activated alcohols with Selectfluor®.

Project description:Herein we disclose a deoxyfluorination of alcohols with an electrophilic fluorine source via visible-light photoredox catalysis. This radical-mediated C-F coupling is capable of fluorinating secondary and tertiary alcohols efficiently, complementing previously reported nucleophilic deoxyfluorination protocols.

| S-EPMC7441851 | biostudies-literature

Visible Light-Emitting Diode Light-Driven Cu0.9Fe0.1@RCAC-Catalyzed Highly Selective Aerobic Oxidation of Alcohols and Oxidative Azo-Coupling of Anilines: Tandem One Pot Oxidation-Condensation to Imidazoles and Imines.

Project description:Here, we have demonstrated visible light-emitting diode light-driven selective and efficient aerobic oxidation of primary/secondary alcohols to aldehydes/ketones and oxidative azo-coupling of anilines using biomass rice husk-derived chemically activated carbon sheet-supported copper-iron bimetallic hybrid nanomaterials (Cu x Fe1-x @RCAC) under oxidant and additive-free conditions. The catalytic activity of the Cu x Fe1-x @RCAC materials has been investigated for the oxidation of alcohols and anilines, and Cu0.9Fe0.1@RCAC was established as the best catalyst. Moreover, a tandem one-pot protocol has been developed for the sequential oxidation of alcohols followed by condensation to functionalized imidazole and imine derivatives in high isolated yields. The hybrid materials were highly robust and stable under the reaction conditions and were recovered simply by filtration and recycled up to 12th run without considerable loss in catalytic activity.

| S-EPMC6941188 | biostudies-literature

Metal/oxide interfacial effects on the selective oxidation of primary alcohols.

Project description:A main obstacle in the rational development of heterogeneous catalysts is the difficulty in identifying active sites. Here we show metal/oxide interfacial sites are highly active for the oxidation of benzyl alcohol and other industrially important primary alcohols on a range of metals and oxides combinations. Scanning tunnelling microscopy together with density functional theory calculations on FeO/Pt(111) reveals that benzyl alcohol enriches preferentially at the oxygen-terminated FeO/Pt(111) interface and undergoes readily O-H and C-H dissociations with the aid of interfacial oxygen, which is also validated in the model study of Cu2O/Ag(111). We demonstrate that the interfacial effects are independent of metal or oxide sizes and the way by which the interfaces were constructed. It inspires us to inversely support nano-oxides on micro-metals to make the structure more stable against sintering while the number of active sites is not sacrificed. The catalyst lifetime, by taking the inverse design, is thereby significantly prolonged.

| S-EPMC5253635 | biostudies-literature

Catalytic radical reduction in aqueous solution via oxidation of biologically-relevant alcohols.

Project description:Metalloenzymes that normally perform catalytic antioxidant or radical-degrading functions, as well as small-molecule complexes that mimic them, can also exert pro-oxidant or radical-forming effects depending on the identity of the terminal reductant. Because nitroxyl radicals function as redox active cocatalysts in the aerobic oxidation of alcohols, we hypothesized that catalytic radical reduction could be achieved via the oxidation of biologically-relevant alcohols. Herein we report an organoruthenium complex (Ru1) that catalyzed reduction of 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonate) radical monoanion (ABTS˙-) to ABTS2- in phosphate buffered saline (pH 7.4) using MeOH, EtOH, i-PrOH, serine, threonine, glucose, arabinose, methyl lactate or dimethyl malate as the terminal reductant. Replacing either the C-H or O-H groups of a -CHOH- moiety resulted in the loss of ABTS˙- reducing ability. Moreover, in conjunction with an alcohol terminal reductant, Ru1 was able to inhibit the oxidation of ABTS2- by H2O2 and horseradish peroxidase, even after multiple successive challenges with excess H2O2 or ABTS˙-. Collectively, these results demonstrate that Ru1 inhibits the oxidative formation of and catalyzes the reduction of radicals in aqueous solution via oxidation of biologically-relevant alcohols.

| S-EPMC6013915 | biostudies-literature

Additive-Mediated Selective Oxidation of Alcohols to Esters via Synergistic Effect Using Single Cation Cobalt Catalyst Stabilized with Inorganic Ligand.

Project description:The direct catalytic oxidation of alcohols to esters is very appealing, but the economical-friendly catalysis systems are not yet well established. Herein, we show that a pure inorganic ligand-supported single-atomic cobalt compound, (NH4)3[CoMo6O18(OH)6] (simplified as CoMo6), could be used as a heterogeneous catalyst and effectively promote this type of reaction in the presence of 30% H2O2 using KCl as an additive. The oxidative cross-esterification of various alcohols (aromatic and aliphatic) could be achieved under mild conditions in nearly all cases, affording the corresponding esters in high yields, including several drug molecules and natural products. Detailed studies have revealed that chloride ion is able to bind to the CoMo6 to form a supramolecular dimer 2(CoMo6?Cl), which can effectively catalyze the reaction via a synergistic effect from chloride ion and CoMo6. Mechanism studies and control reactions demonstrate that the esterification proceeds via the key oxidative immediate of aldehydes.

| S-EPMC6998037 | biostudies-literature