Browse
Submit Data
Databases
API
Help

Dataset Information

23 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

DABCO-promoted photocatalytic C-H functionalization of aldehydes.

ABSTRACT: Herein we present a direct application of DABCO, an inexpensive and broadly accessible organic base, as a hydrogen atom transfer (HAT) abstractor in a photocatalytic strategy for aldehyde C-H activation. The acyl radicals generated in this step were arylated with aryl bromides through a well stablished nickel cross-coupling methodology, leading to a variety of interesting aryl ketones in good yields. We also performed computational calculations to shine light in the HAT step energetics and determined an optimized geometry for the transition state, showing that the hydrogen atom transfer between aldehydes and DABCO is a mildly endergonic, yet sufficiently fast step. The same calculations were performed with quinuclidine, for comparison of both catalysts and the differences are discussed.

SUBMITTER: Maia da Silva Santos B

PROVIDER: S-EPMC8712972 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Regioselective, Photocatalytic α-Functionalization of Amines.

Project description:Photocatalytic α-functionalization of amines provides a mild and atom-economical means to synthesize α-branched amines. Prior examples featured symmetrical or electronically biased substrates. Here we report a controllable α-functionalization of amines in which regioselectivity can be tuned with minor changes to the reaction conditions.

| S-EPMC8475292 | biostudies-literature

Photocatalytic acyl azolium-promoted alkoxycarbonylation of trifluoroborates.

Project description:Despite recent advancements in the selective generation and coupling of organic radical species, the alkoxycarbonyl radical remains underexplored relative to other carbon-containing radical species. Drawing inspiration from new strategies for generating acyl radical equivalents utilizing dual N-heterocyclic carbene catalysis and photocatalysis, we have prepared dimethylimidazolium esters that can function as an alkoxycarbonyl radical surrogate under photocatalytic conditions. We demonstrate the synthetic utility of these azolium-based partners through the preparation of esters arising from the coupling of this radical surrogate with an oxidatively generated alkyl radical.

| S-EPMC8274565 | biostudies-literature

Multi-Functionalization of Polymers by Strain-Promoted Cycloadditions.

Project description:We report here a synthetic route to oxime, azide and nitrone-bearing copolymers via reversible addition-fragmentation chain transfer copolymerization of 4-vinylbenzaldehyde and 1-(chloromethyl)-4-vinylbenzene with styrene. The azide and nitrone moieties could be employed in strain-promoted 1,3-dipolar cycloadditions with various functionalized dibenzocyclooctynols (DIBO) for metal-free post-functionalization of the polymers. In situ oxidation of the oximes with hypervalent iodine gave nitrile oxides, which could also be employed as 1,3-dipoles for facile cycloadditions with DIBO derivatives. Kinetic measurements demonstrated that the pendant nitrile oxides reacted approximately twenty times faster compared to similar cycloadditions with azides. A block copolymer, containing azide and oxime groups in segregated blocks, served as a scaffold for attachment of hydrophobic and hydrophilic moieties by sequential strain-promoted alkyne-azide and strain-promoted alkyne-nitrile oxide cycloadditions. This sequential bi-functionalization approach made it possible to prepare in a controlled manner multi-functional polymers that could self-assemble into well-defined nanostructures.

| S-EPMC3916133 | biostudies-literature

Ligand-Promoted meta-C-H Functionalization of Benzylamines.

Project description:Meta-C-H functionalization of benzylamines has been developed using a PdII /transient mediator strategy. Using 2-pyridone ligands and 2-carbomethoxynorbornene (NBE-CO2 Me) as the mediator, arylation, amination, and chlorination of benzylamines are realized. This protocol features a broad substrate scope and is compatible with heterocylic coupling partners. Moreover, the loading of the Pd can be lowered to 2.5?mol?% by using the optimal ligand.

| S-EPMC5512280 | biostudies-literature

Palladium Catalyzed meta-C-H Functionalization of Masked Aromatic Aldehydes.

Project description:Palladium catalyzed meta-C-H functionalization enabled by transient mediators has the potential to extend the utility of directed ortho-C-H functionalization to remote positions. However, there have been no reports of palladium catalyzed meta-C-H functionalization of aromatic aldehyde derivatives, which are highly versatile intermediates in organic synthesis. Herein we report the development of a directing group that, in the presence of a norbornene derived mediator and an appropriate pyridone ligand, allows palladium catalyzed meta-C-H functionalization of masked aromatic aldehydes. Mechanistic insight regarding the impact of the directing group length on this catalysis is also discussed.

| S-EPMC6301045 | biostudies-literature

Site-Selective Photocatalytic Functionalization of Peptides and Proteins at Selenocysteine

Project description:The importance of modified peptides and proteins for applications in drug discovery, and for illuminating biological processes at the molecular level, has fueled a demand for efficient methods that facilitate the precise modification of these biomolecules. Herein, we describe the development of a photocatalytic method for the rapid and efficient dimerization and sitespecific functionalization of peptide and protein diselenides. This methodology, dubbed the photocatalytic diselenide contraction (PDC), involves irradiation at 450 nm in the presence of an iridium photocatalyst and a phosphine and results in rapid and clean conversion of diselenides to reductively stable selenoethers. A mechanism for this unprecedented photocatalytic transformation is proposed, which is supported by photoluminescence spectroscopy and density functional theory calculations. The utility of the PDC transformation is highlighted through the dimerization of selenopeptides, and by the generation of two families of protein conjugates via the site-selective modification of calmodulin containing the 21st amino acid selenocysteine, and the C-terminal modification of a ubiquitin diselenide.

2022-10-25 | PXD037525 | Pride

Photocatalytic carbanion generation - benzylation of aliphatic aldehydes to secondary alcohols.

Project description:We present a redox-neutral method for the photocatalytic generation of carbanions. Benzylic carboxylates are photooxidized by single electron transfer; immediate CO2 extrusion and reduction of the in situ formed radical yields a carbanion capable of reacting with aliphatic aldehydes as electrophiles giving the Grignard analogous reaction product.

| S-EPMC6524566 | biostudies-literature

Photocatalytic redox-neutral hydroxyalkylation of <i>N</i>-heteroaromatics with aldehydes.

Project description:Hydroxyalkylation of N-heteroaromatics with aldehydes was achieved using a binary hybrid catalyst system comprising an acridinium photoredox catalyst and a thiophosphoric acid organocatalyst. The reaction proceeded through the following sequence: (1) photoredox-catalyzed single-electron oxidation of a thiophosphoric acid catalyst to generate a thiyl radical, (2) cleavage of the formyl C-H bond of the aldehyde substrates by a thiyl radical acting as a hydrogen atom transfer catalyst to generate acyl radicals, (3) Minisci-type addition of the resulting acyl radicals to N-heteroaromatics, and (4) a spin-center shift, photoredox-catalyzed single-electron reduction, and protonation to produce secondary alcohol products. This metal-free hybrid catalysis proceeded under mild conditions for a wide range of substrates, including isoquinolines, quinolines, and pyridines as N-heteroaromatics, as well as both aromatic and aliphatic aldehydes, and tolerated various functional groups. The reaction was applicable to late-stage derivatization of drugs and their leads.

| S-EPMC8163015 | biostudies-literature

Sequential Catalytic Functionalization of Aryltriazenyl Aldehydes for the Synthesis of Complex Benzenes.

Project description:We demonstrate that aryltriazenes can promote three distinctive types of C-H functionalization reactions, allowing the preparation of complex benzene molecules with diverse substitution patterns. 2-Triazenylbenzaldehydes are shown to be efficient substrates for Rh(I)-catalyzed intermolecular alkyne hydroacylation reactions. The resulting triazene-substituted ketone products can then undergo either a Rh(III)-catalyzed C-H activation, or an electrophilic aromatic substitution reaction, achieving multifunctionalization of the benzene core. Subsequent triazene derivatization provides traceless products.

| S-EPMC8291607 | biostudies-literature

Acetic Acid Promoted Redox Annulations with Dual C-H Functionalization.

Project description:Amines such as 1,2,3,4-tetrahydroisoquinoline undergo redox-neutral annulations with 2-alkylquinoline-3-carbaldehydes as well as the corresponding 4-alkyl isomers and pyridine analogues. These processes involve dual C-H bond functionalization. Acetic acid is used as a cosolvent and acts as the sole promoter of these transformations.

| S-EPMC5460294 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

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