Applications of ytterbium(II) reagent as Grignard reagent and single electron transfer reagent in the synthesis of 3-substituted-2-oxindoles

The utilities of ytterbium(II) reagent, both as nucleophilic reagent and single electron transfer reagent in the reaction of isatin derivatives with ytterbium(II) reagent are reported for the first time in this paper. From a synthetic point of view, a general, efficient, and experimentally simple one-pot method for preparation of 3-substituted-2-oxindoles was developed.

Hydroxylamines as One-Atom Nitrogen Sources for Metal-Catalyzed Cycloadditions

Transition-metal-catalyzed C–N bond formation is one of the most important pathways to synthesize N-heterocycles. Hydroxylamines can be transformed into a nucleophilic reagent to react with a carbon cation or coordinate with a transition metal; it can also become an electrophilic nitrogen source to react with arenes, alkenes, and alkynes. In this short review, the progress made on transition-metal-catalyzed cycloadditions with hydroxylamines as a nitrogen source is summarized.1 Introduction2 Cycloaddition To Form Aziridine Derivatives2.1 Intramolecular Cycloaddition To Form Aziridine Derivatives2.2 Intermolecular Cycloaddition To Form Aziridine Derivatives3 Cycloaddition To Form Indole Derivatives4 Cycloaddition To Form Other N-Heterocycles4.1 Aza-Heck-Type Amination Reactions4.2 Nitrene Insertion Amination Reactions4.3 Intramolecular Nucleophilic and Electrophilic Amination Reactions5 Conclusion and Outlook

Deoxygenative Nucleophilic Difluoromethylselenylation of Carboxylic Acids and Alcohols with BT-SeCF2H

The benzothiazolium salt BT-SeCF2H is introduced as an efficient nucleophilic reagent for transferring difluoromethylselenyl groups onto organic molecules. SeCF2H-Containing selenoesters could be prepared upon deoxygenative substitution of readily available carboxylic...

8-Hydroxy-5-nitroquinoline as a C-nucleophilic reagent in the reaction of C, C-coupling with quinazoline

The first example of the reaction of 5-nitro-8-hydroxyquinoline as a C-nucleophile with quinazoline is described. As a result of the reaction of C, C-coupling, a stable σ-adduct containing the drug nitroxalin on a heterocyclic carrier was obtained. The structure of the resulting adduct was confirmed by 2D 1H-13C HSQC, 1H-13C HMBC, and 1H-15N HMBC spectra.

Demethylation of Alkali Lignin with Halogen Acids and Its Application to Phenolic Resins

Lignin, a byproduct from the chemical processing of lignocellulosic biomass, is a polyphenolic compound that has potential as a partial phenol substitute in phenolic adhesive formulations. In this study, HBr and HI were used as reagents to demethylate an alkali lignin (AL) to increase its hydroxyl content and thereby enhance its reactivity for the preparation of phenolic resins. Analyses by FT-IR, 1H-NMR and 2D-NMR(HSQC) demonstrated both a decrease in methoxyl groups and an increase in hydroxyl groups for each demethylated lignin (DL). In addition, the molar amounts of phenolic hydroxyls, determined by 1H-NMR, increased to 0.67 mmol/g for the HI-DL, and 0.64 mmol/g for the HBr-DL, from 0.52 mmol/g for the AL. These results showed that HI, a stronger nucleophilic reagent than HBr, provided a higher degree of AL demethylation. Lignin-containing resins, prepared by copolymerization, met the bonding strength standard for exterior plywood with DL used to replace as much as 50 wt.% of phenol. The increased hydroxyl contents resulting from the lignin demethylations also imparted faster cure times for the lignin-containing resins and lower formaldehyde emissions. Altogether, the stronger nucleophilicity of HI, compared to HBr, impacted the degree of lignin demethylation, and carried through to measurable differences the thermal properties and performance of the lignin-containing PF resins.

Synthesis of multi-substituted indene derivatives from aryl, vinyl, and alkyl/aryl carbinols

A divergent approach to highly substituted functionalized indenes has been developed. The two-step reaction involving nucleophilic addition reaction of aryl vinyl ketone, an ideal intermediate with aryl or alkyl nucleophilic reagent, followed by electrocyclization (Nazarov cyclization) in the presence of Lewis acid catalyst afforded indene derivatives in good to excellent yield.

[Ag(bpy)(PPhtBu2)(OCF3)]: a stable nucleophilic reagent for chemoselective and stereospecific trifluoromethoxylation of secondary alkyl nosylates

The development of a thermally stable and light-insensitive nucleophilic trifluoromethoxylative reagent [Ag(bpy)(PPhtBu2)(OCF3)] 2, which was synthesized in high yields via a three-step one-pot process from easily available trifluoromethyl triflate (TFMT) and AgF at room temperature, is described.