The ynamide functional group activates carbon–carbontriple bonds through an attached nitrogen atom that bears electron-withdrawing group. As a result, the alkyne has both electrophilic and nucleophilic properties. Through selection of to nitrogen, chemists can modulate electronic properties reactivity ynamides, making these groups versatile synthetic building blocks. reactions ynamides also lead directly nitrogen-containing products, which provides access important structural motifs found in...

Metal carbenes are highly versatile species that mediate various transformations. Recent advances in gold catalysis have allowed catalytic access to α-oxo metal from the alkyne functionality. Compared with traditional methods rely upon metal-catalyzed decomposition of diazo precursors, generation this synthon occurs an environmentally more appealing fashion by gold-catalyzed oxygenation. Hydroxylamine derivatives typically prepared hydroxylamine salts cheap and can be handled without special...

Sicher und atomökonomisch: Die intramolekulare Redoxreaktion eines Alkin-Nitrons, katalysiert durch ein elektrophiles Metall, liefert Azomethin-Ylide (siehe Schema; M: Metall). Diese atomökonomische Synthese von Azomethin-Yliden kommt ohne explosionsgefährliche Diazoderivate aus. können über eine dipolare Cycloadditionskaskade in Azabicyclo[3.2.1]octane überführt werden. Supporting information for this article is available on the WWW under...

Just another Mannich Monday: A cascade intramolecular redox-pinacol-Mannich-Michael reaction sequence catalyzed by gold complexes can be used to generate a variety of structures including spirocycles, 1-aminoindanes, and 5,6-fused azabicycles that have quaternary carbon center. The is characterized complete atom-economy, high diastereoselectivity, remarkable efficiency through tandem reactions.

We report geometry-dependent cyclizations of o-alkynylaryl ketoximes and nitrones catalyzed by gold complexes. (E)-Ketoximes undergo N-attack to give isoquinoline-N-oxides. In sharp contrast, (Z)-ketoximes unprecedented O-nucleophilic attack, followed a redox cascade leading novel catalytic entry isoindoles diverse scope. The structure an isoindole was unambiguously supported X-ray crystallography. demonstrated the generality synthesis from either (Z)-oximes or nitrones, presented...

Abstract Au I ‐catalyzed cyclization of N ‐Boc propargylamines into 4‐alkylidene oxazolidin‐2‐ones is described. This modularapproach provides access to a variety nonproteogenic 4‐substituted oxazolidinones that are important in asymmetric synthesis and biological applications. The current flexible route characterized by low catalyst loading, mild conditions, operational simplicity.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Golden touch: Gold-catalyzed reaction of N-sulfonyl hydroxylamines with terminal alkyne led to 3-pyrrolidinones by means an oygen-transfer redox reaction. This protocol constitutes a direct method for forming α-amino carbonyl compounds. In sharp contrast, those internal alkynes underwent 1,3-sulfonyl migration leading 3-sulfonyl cyclic nitrones. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or...

A gold-catalyzed intermolecular reaction of propiolic acids with alkenes led to a [4 + 2] annulation or enyne cross metathesis. The proceeds net cis-addition respect and provides an expedient route α,β-unsaturated δ-lactones, for which preliminary asymmetric reactions were also demonstrated. For 1,2-disubstituted alkenes, unprecedented metathesis occurred give 1,3-dienes in completely stereospecific fashion. DFT calculations experiments indicated that the cyclobutene derivatives are not...

Total syntheses of a series chromane natural products that contain cyclobutane ring are described. A unified theme in the strategy employed for all these is an oxa-[3 + 3] annulation constructing nucleus and stepwise cationic [2 2] cycloaddition formation. More importantly, two reactions could be rendered tandem, thereby providing expeditious approach to this family products.

Mannich und mehr: Eine Sequenz aus intramolekularer Redox-, Pinacol-, Mannich- Michael-Reaktion führt unter Goldkatalyse zu verschiedenartigen Strukturen mit quartären Kohlenstoffzentren, z. B. Spirocyclen, 1-Aminoindanen anellierten 5,6-Azabicyclen. Die Reaktion zeichnet sich durch vollständige Atomökonomie, hohe Diastereoselektivität eine erstaunliche Effizienz aus.

Xenorhabdus hominickii ANU1 is known to be an entomopathogenic bacterium symbiotic nematode Steinernema monticolum . Another bacterial strain X. DY1 was isolated from a local population of S. This found exhibit high insecticidal activities against lepidopteran and coleopteran species after hemocoelic injection. However, these two strains exhibited significant variations in activities, with being more potent than strain. To clarify their virulence difference, culture broths were compared for...

The first gold-catalyzed intermolecular coupling of alkynoates and allylic ethers invoking alkoxy addition [3,3]-sigmatropic rearrangement as the key mechanism has been developed. Remarkably, reaction showed complete chemoselectivity toward pathway initiated by to alkynes. This unprecedented reactivity led a new access diversely substituted β-alkoxyacrylates in highly efficient manner.

As strong as an aux: An electronically-tuned hydroxylamine functions excellent chiral auxiliary for [3+2] cycloaddition of the azomethine ylides generated in-situ from gold-catalyzed redox reaction alkynyl nitrones. Detailed facts importance to specialist readers are published "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by authors. Please note: The publisher is responsible content functionality any supporting...

Development of an oxa-[3+3] annulation vinyliminium salts with resorcinols as a 1,3-diketo equivalent is described. This constitutes cascade Knoevenagel condensation–oxa-electrocyclization leading to direct access chromenes. A series attempts was made demonstrate its synthetic utility in natural product synthesis, culminating total synthesis (±)-rhododaurichromanic acid that also featured intramolecular Gassman-type cationic [2+2] cycloaddition.

Silver trifluoromethanesulfonate efficiently catalyzes the cyclization of 2-alkynylbenzaldoxime derivatives into corresponding isoquinoline-N-oxides. The current protocol provides a direct route to latter skeleton under very mild reaction condition.

Brønsted acid-catalyzed addition of pyridine- N -oxides to ynamides forms -enoxypyridinium ions that are functionally equivalent α-carbonyl cations.

Abstract Serotonin (5-hydroxytryptamine: 5-HT) is a biogenic monoamine that mediates immune responses and modulates nerve signal in insects. Se-5HTR , specific receptor of serotonin, has been identified the beet armyworm, Spodoptera exigua . It classified into subtype 7 among known 5HTRs. was expressed all developmental stages S tested tissues larval stage. Its expression up-regulated hemocytes fat body response to challenge. RNA interference (RNAi) exhibited significant immunosuppression by...

Gold(I)-catalyzed intramolecular hydroamination of O-propargyl-N-Boc-hydroxylamine is reported. The present ­method provides a novel, catalytic, and mild approach to 2,5-dihydroisoxazole derivatives. In addition, mechanism N-O cleavage as side reaction well desired cyclization proposed.

Abstract A one‐pot synthesis of 2‐amido‐3‐bromobenzo[ b ]thiophenes based on C−N coupling and oxidative bromocyclization reactions was developed. This enables a modular approach to obtain diverse substituents at the C2 position benzothiophenes by employing structurally modified sulfonamides. Oxidative cyclization driven Selectfluor represents previously unreported recycling method for bromide anion byproducts bond step. The details study are described fully herein.

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at glance that was extracted from about 200 leading journals. To access of an article which published elsewhere, please select “Full Text” option. The original trackable via the “References”

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at glance that was extracted from about 200 leading journals. To access of an article which published elsewhere, please select “Full Text” option. The original trackable via the “References”

Abstract Serotonin (5-hydroxytryptamine: 5-HT) is a biogenic monoamine that mediates immune responses and modulates nerve signal in insects. Se-5HTR , specific receptor of serotonin, has been identified the beet armyworm, Spodoptera exigua. It classified into subtype 7 among known 5HTRs. was expressed all developmental stages S. tested tissues larval stage. Its expression up-regulated hemocytes fat body response to challenge. RNA interference (RNAi) exhibited significant immunosuppression by...

Abstract Review: 71 refs.