Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Merging the Norrish type I reaction and transition metal catalysis: photo- and Rh-promoted borylation of C-C σ-bonds of aryl ketones.

ABSTRACT: Synthesis of arylboronates via borylation of C-C σ-bonds of aryl ketones was achieved by the combined use of photoenergy and a Rh catalyst. The cooperative system enables α-cleavage of photoexcited ketones to generate aroyl radicals via the Norrish type I reaction, which are successively decarbonylated and borylated with the rhodium catalyst. This work establishes a new catalytic cycle merging the Norrish type I reaction and Rh catalysis and demonstrates the new synthetic utility of aryl ketones as aryl sources for intermolecular arylation reactions.

SUBMITTER: Fujimaki Y

PROVIDER: S-EPMC9945184 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Merging the Norrish type I reaction and transition metal catalysis: photo- and Rh-promoted borylation of C-C σ-bonds of aryl ketones.

Fujimaki Yuki Y Iwasawa Nobuharu N Takaya Jun J

Chemical science 20230126 8

Synthesis of arylboronates <i>via</i> borylation of C-C σ-bonds of aryl ketones was achieved by the combined use of photoenergy and a Rh catalyst. The cooperative system enables α-cleavage of photoexcited ketones to generate aroyl radicals <i>via</i> the Norrish type I reaction, which are successively decarbonylated and borylated with the rhodium catalyst. This work establishes a new catalytic cycle merging the Norrish type I reaction and Rh catalysis and demonstrates the new synthetic utility o ...[more]

PMID: 36845921

Similar Datasets

Rh-catalyzed alkoxycarbonylation of unactivated alkyl chlorides† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d2sc04103k

Project description:A general rhodium-catalyzed selective carbonylative coupling of unactivated alkyl chlorides with aliphatic alcohols or phenols to the corresponding esters is presented for the first time. Crucial for this transformation is the addition of sodium iodide, which provides in situ more active alkyl iodides. In the presence of a Rh(i)-DPPP catalyst system diverse esters (81 examples) including industrially relevant acetates from chloro- and dichloromethane can be prepared in a straightforward manner in up to 95% isolated yield. The used ligand not only affects the selectivity of the carbonylation reaction but also controls the selectivity of the preceding halide exchange step. An efficient and convenient rhodium-catalyzed alkoxycarbonylation of unactivated alkyl chlorides was developed for the first time. More than 80 examples of esters were prepared directly from readily available substrates with often high selectivity.

| S-EPMC9682885 | biostudies-literature

Hidden hydrophobicity impacts polymer immunogenicity† † Electronic supplementary information (ESI) available: Experimental details and supplementary figures. See DOI: https://doi.org/10.1039/d2sc07047b

Project description:Antibodies against poly(ethylene glycol) (PEG) have been found to be the culprit of side reactions and efficacy loss of a number of PEGylated drugs. Fundamental mechanisms of PEG immunogenicity and design principles for PEG alternatives still have not been fully explored. By using hydrophobic interaction chromatography (HIC) under varied salt conditions, we reveal the “hidden” hydrophobicity of those polymers which are generally considered as hydrophilic. A correlation between the hidden hydrophobicity of a polymer and its polymer immunogenicity is observed when this polymer is conjugated with an immunogenic protein. Such a correlation of hidden hydrophobicity vs. immunogenicity for a polymer also applies to corresponding polymer–protein conjugates. Atomistic molecular dynamics (MD) simulation results show a similar trend. Based on polyzwitterion modification and with this HIC technique, we are able to produce extremely low-immunogenic protein conjugates as their hydrophilicity is pushed to the limit and their hydrophobicity is eliminated, breaking the current barriers of eliminating anti-drug and anti-polymer antibodies. The hidden hydrophobicity of conventional polymers widely considered as hydrophilic is closely related to their immunogenicity when they are conjugated to immunogenic proteins.

| S-EPMC9945064 | biostudies-literature

Microwave-assisted synthesis of octahedral Rh nanocrystals and their performance for electrocatalytic oxidation of formic acid † † Electronic supplementary information (ESI) available: Experimental details, TEM, SEM images and cyclic voltamograms. See DOI: https://doi.org/10.1039/d2ra07445a

Project description:Uniform and well-defined octahedral Rh nanocrystals were rapidly synthesized in a domestic microwave oven for only 140 s of irradiation by reducing Rh(acac)3 with tetraethylene glycol (TEG) as both a solvent and a reducing agent in the presence of an appropriate amount of KI, didecyl dimethyl ammonium chloride (DDAC), ethylene diamine (EDA) and polyvinylpyrrolidone (PVP). KI, DDAC and EDA were essential for the creation of octahedral Rh nanocrystals. Electrochemical measurements showed a significantly enhanced electrocatalytic activity and stability for the as-prepared octahedral Rh nanocrystals compared with commercial Rh black. Octahedral Rh nanocrystals were rapidly synthesized in a domestic microwave oven for only 140 s of irradiation by reducing Rh(acac)3 with tetraethylene glycol as both a solvent and a reducing agent.

| S-EPMC9832441 | biostudies-literature

The power of microdroplet photochemistry† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d4sc00056k

Project description: Not available

| S-EPMC10915808 | biostudies-literature

Total synthesis of bi-magnolignan† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3ra01121f

Project description:Bi-magnolignan, isolated from the leaves of Magnolia officinalis, has shown excellent physiological activity against tumor cells. An efficient strategy for the first total synthesis of bi-magnolignan is reported. The bi-dibenzofuran skeleton was constructed via functional group interconversions of commercially available materials 1,2,4-trimethoxybenzene and 4-allylanisole. Then, the dibenzofuran skeleton was afforded by subsequent Suzuki coupling and intramolecular dehydration. The total synthesis of natural product was accomplished through FeCl3 catalyzed oxidative coupling. The first total synthesis of bi-magnolignan in eight steps from commercially available starting materials has been developed.

| S-EPMC10018648 | biostudies-literature

Catalytic photochemical enantioselective α-alkylation with pyridinium salts† † Electronic supplementary information (ESI) available: Experimental details, characterization data, and spectral data (PDF). See DOI: https://doi.org/10.1039/d2sc05654b

Project description:We have developed a chiral amine catalyzed enantioselective α-alkylation of aldehydes with amino acid derived pyridinium salts as alkylating reagents. The reaction proceeds in the presence of visible light and in the absence of a photocatalyst via a light activated charge-transfer complex. We apply this photochemical stereoconvergent process to the total synthesis of the lignan natural products (−)-enterolactone and (−)-enterodiol. Mechanistic studies support the ground-state complexation of the reactive components followed by divergent charge-transfer processes involving catalyst-controlled radical chain and in-cage radical combination steps. We have developed a chiral amine catalyzed enantioselective α-alkylation of aldehydes with amino acid derived pyridinium salts as alkylating reagents.

| S-EPMC9847668 | biostudies-literature

Boric acid catalysed hydrolysis of peroxyacids† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3ra01046e

Project description:This study shows for the first time that boric acid catalyses the hydrolysis of peroxyacids, resulting in an approximately 12-fold increase in hydrolysis rate for both peracetic acid (PAA) and 3-chloroperbenzoic acid (MCPBA) when 0.1 M boric acid is present. The maximum rate of hydrolysis occurs at pH 9 and pH 8.4 for PAA and MCPBA respectively. In contrast, carbonate buffer does not enhance the rate of PAA hydrolysis. The reaction was followed by measuring the initial rate of hydrogen peroxide formation using a specific Ti(iv) complexation method. The study of the hydrolysis reaction requires the presence of 2 × 10−5 M each of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine tetramethylene phosphonic acid (EDTMP) in all solutions in order to chelate metal ions across the full pH range (3 to 13) that would otherwise contribute to peroxyacid decomposition. Catalysis of peroxyacid hydrolysis is most likely effected by the triganol boric acid acting as a Lewis acid catalyst, associating with the peroxide leaving group in the transition state to reduce the leaving group basicity. The products of the reaction are the well characterised monoperoxoborate species and the parent carboxylic acid. Analysis of the pH and borate dependence data reveals that in addition to a catalytic pathway involving a single boric acid molecule, there is a significant pathway involving either (a) two boric acid molecules or (b) the polyborate species, B3O3(OH)4−. Knowledge about catalytic mechanisms for the loss of peroxyacids through hydrolysis is important because they are widely used in reagents in a range of oxidation, bleaching and disinfection applications. Boric acid catalyses the hydrolysis of peroxyacids, with possible pathways involving one and two molecules of boric acid as well as polyborate species.

| S-EPMC10103745 | biostudies-literature

AI facilitated fluoro-electrochemical phytoplankton classification† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3sc01741a

Project description:Marine phytoplankton is extremely diverse. Counting and characterising phytoplankton is essential for understanding climate change and ocean health not least since phytoplankton extensively biomineralize carbon dioxide whilst generating 50% of the planet's oxygen. We report the use of fluoro-electrochemical microscopy to distinguish different taxonomies of phytoplankton by the quenching of their chlorophyll-a fluorescence using chemical species oxidatively electrogenerated in situ in seawater. The rate of chlorophyll-a quenching of each cell is characteristic of the species-specific structural composition and cellular content. But with increasing diversity and extent of phytoplankton species under study, human interpretation and distinction of the resulting fluorescence transients becomes increasingly and prohibitively difficult. Thus, we further report a neural network to analyse these fluorescence transients, with an accuracy >95% classifying 29 phytoplankton strains to their taxonomic orders. This method transcends the state-of-the-art. The success of the fluoro-electrochemical microscopy combined with AI provides a novel, flexible and highly granular solution to phytoplankton classification and is adaptable for autonomous ocean monitoring. Schematic of fluoro-electrochemical microscopy. (a) Cartoon E. huxleyi is green under normal light, but (b) emits red fluorescence under UV. (c) Placed near an oxidizing electrode, its fluorescence fades and ultimately (d) “switches off”.

| S-EPMC10246652 | biostudies-literature

Electrically conductive [Fe4S4]-based organometallic polymers† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3sc02195e

Project description: Not available

| S-EPMC10599474 | biostudies-literature

α-Amino bicycloalkylation through organophotoredox catalysis† † Electronic supplementary information (ESI) available: Experimental procedures, computational details, copies of 1H and 13C NMR spectra. See DOI: https://doi.org/10.1039/d4sc01368a

Project description: Not available

| S-EPMC11253163 | biostudies-literature