18 research outputs found
Metal-Free Oxidative Spirocyclization of Hydroxymethylacrylamide with 1,3-Dicarbonyl Compounds: A New Route to Spirooxindoles
A metal-free oxidative spirocyclization of hydroxymethylacrylamide with 1,3-dicarbonyl compounds is described. The reaction proceeds through tandem dual C–H functionalization and intramolecular dehydration, in which two new C–C bonds and one C–O bond were formed. This method affords a novel and straightforward access to various spirooxindoles under mild conditions
Redox-Neutral Cyanoalkylation/Cyclization of Olefinic 1,3‑Dicarbonyls with Cycloketone Oxime Esters: Access to Cyanoalkylated Dihydrofurans
Metal-catalyzed cyanoalkylation/cyclization
of olefinic 1,3-dicarbonyls
with cycloketone oxime esters has been developed under redox-neutral
conditions. This protocol provided a straightforward approach to diverse
cyanoalkylated 2,3-dihydrofurans via a tandem ring-opening/addition/cyclization
process
Direct C–H Cyanoalkylation of Heteroaromatic <i>N</i>‑Oxides and Quinones via C–C Bond Cleavage of Cyclobutanone Oximes
A direct
C–H cyanoalkylation of heteroaromatic <i>N</i>-oxides
and quinones with cyclobutanone oximes is reported. This
redox-neutral, operationally simple cyanoalkylation reaction is successfully
amenable to a wide range of heteroaromatic <i>N</i>-oxides,
quinones, and cyclobutanone oximes. A novel catalytic system consisting
of a nickel source proved crucial for cleavage of the C–C bond
of cyclobutanone oximes and for selective C–C bond formation
over β-hydride elimination. Mechanistic studies suggest that
a radical intermediate might be involved in this transformation
Copper-Catalyzed Redox-Neutral Cyanoalkylarylation of Activated Alkenes with Cyclobutanone Oxime Esters
The copper-catalyzed cyclization
of activated alkenes with cyclobutanone <i>O</i>-acyl oximes
under redox-neutral conditions has been reported.
This facile protocol provided an efficient approach to a variety of
cyanoalkylated oxindoles and dihydroquinolin-2Â(1<i>H</i>)-ones with a broad substrate scope and excellent functional group
tolerance. In this reaction, sequential C–C bond cleavage,
radical addition, and cyclization processes were involved, wherein
multiple bonds were constructed in a one-pot reaction. Mechanistic
studies suggest that the reaction probably proceeded via a radical
pathway
Iron-Catalyzed Decarboxylative Olefination of Cycloketone Oxime Esters with α,β-Unsaturated Carboxylic Acids via C–C Bond Cleavage
An
iron-catalyzed redox-neutral, decarboxylative olefination of
cycloketone oxime esters with α,β-unsaturated carboxylic
acids has been developed. This reaction involves an iminyl radical
mediated C–C bond cleavage/radical addition/decarboxylation
cascade. This protocol is highlighted by its low-cost catalytic system
and readily accessible starting materials, as well as broad substrate
scope, thus providing facile access to structurally diverse cyano-containing
alkenes
Microbiological characteristics of a novel species most closely related to 'Bergeyella cardium' as a pathogen of infectious endocarditis - Fig 1
<p><b>Morphological characteristics of strain PU13217, a novel species, on Columbia Blood agar (a to d) and its Gram staining property (e).</b> Incubation conditions: <b>1a</b> and <b>1b</b>, 35°C + 5% CO<sub>2</sub>, 2 days; <b>1c</b> and <b>1d</b>, 35°C + 5% CO<sub>2</sub>, 5 days.</p
Phylogenetic tree based on the 16S rRNA sequences of strain PU13217, a novel species, and type strains of other closely related species.
<p><i>Planobacterium taklimakanense</i> X-65 was used as the outgroup.</p
Metal-Free, Visible-Light-Promoted Decarboxylative Radical Cyclization of Vinyl Azides with <i>N</i>‑Acyloxyphthalimides
A visible-light-mediated decarboxylative
cyclization of <i>N</i>-acyloxylphthalimides with vinyl
azides has been developed
under metal-free conditions. This protocol features mild conditions,
a broad substrate scope, and an excellent functional group tolerance,
thus providing a facile and efficient access to substituted phenanthridines.
Control experiments revealed that the reaction proceeded via a radical
process
Minimum inhibitory concentrations (MICs) of strain PU13217 to sixteen antimicrobial agents.
<p>Minimum inhibitory concentrations (MICs) of strain PU13217 to sixteen antimicrobial agents.</p
Nickel-Catalyzed Modular Four-Component 1,4-Alkylcarbonylation of 1,3-Enynes to Tetra-Substituted CF<sub>3</sub>–Allenyl Ketones
The
modular four-component carbonylation of unsaturated hydrocarbons
represents an elegant strategy for the one-pot synthesis of complex
carbonyl compounds. However, this strategy is currently focused on
the 1,2-difunctionalization of olefins or alkynes, and the 1,4-alkylcarbonylation
of 1,3-enynes remains unexplored. In this study, we report a Ni-catalyzed
1,4-alkylcarbonylation of CF3-containing 1,3-enynes under
1 atm of CO, which affords the tetra-substituted CF3-allenyl
ketones with good yields and selectivity. This protocol features mild
conditions, broad substrate scope, and acceptable functional group
compatibility. Control experiments revealed that the reactivity of
oxime esters (regulated by leaving groups) and polarity matching are
crucial for the success of this four-component cascade. Preliminary
mechanistic studies suggest that the acyl nickel complex is a key
intermediate in this transformation