AbstractDie Methylaminodiazonium‐Kationen [CH3N(H)N2]+ und [CF3N(H)N2]+ wurden als ihre bei niedriger Temperatur stabilen [AsF6]‐Salze durch Protonierung von Azidomethan und Azidotrifluormethan in supersauren Systemen hergestellt. Sie wurden durch NMR‐ und Raman‐Spektroskopie charakterisiert. Ein eindeutiger Nachweis der Protonierungsstelle wurde durch die Kristallstrukturen beider Salze erhalten, welche die Bildung der Alkylaminodiazonium‐Ionen bestätigte. Die Lewis‐Addukte CH3N3⋅AsF5 und CF3N3⋅AsF5 wurden ebenfalls hergestellt und durch Tieftemperatur‐NMR‐ und Raman‐Spektroskopie sowie im Falle von CH3N3⋅AsF5 durch Röntgenstrukturbestimmung charakterisiert. Elektronische Strukturberechnungen wurden durchgeführt, um zusätzliche Einblicke zu erhalten. Versuche zur elektrophilen Aminierung von Aromaten wie Benzol und Toluol mit Methyl‐ und Trifluormethylamino‐Diazonium‐Ionen waren erfolglos.

The methylamino diazonium cations [CH3 N(H)N2 ]+ and [CF3 N(H)N2 ]+ were prepared as their low-temperature stable [AsF6 ]- salts by protonation of azidomethane and azidotrifluoromethane in superacidic systems. They were characterized by NMR and Raman spectroscopy. Unequivocal proof of the protonation site was obtained by the crystal structures of both salts, confirming the formation of alkylamino diazonium ions. The Lewis adducts CH3 N3 ⋅AsF5 and CF3 N3 ⋅AsF5 were also prepared and characterized by low-temperature NMR and Raman spectroscopy, and also by X-ray structure determination for CH3 N3 ⋅AsF5 . Electronic structure calculations were performed to provide additional insights. Attempted electrophilic amination of aromatics such as benzene and toluene with methyl- and trifluoromethylamino diazonium ions were unsuccessful.

An effective synthesis of highly functionalized N-perfluoroalkyl-1,2,3-triazoles from azidoperfluoroalkanes has been achieved. In situ generated enamines readily participate in the azide-carbonyl [3 + 2] cycloaddition, providing a facile way to fully substituted triazole frameworks in good to excellent yields. The synthetic value of these triazoles was shown in the synthesis of perfluorinated 1,5-disubstituted triazoles by hydrolysis and decarboxylation.

We report an efficient and scalable synthesis of azidotrifluoromethane (CF3 N3 ) and longer perfluorocarbon-chain analogues (RF N3 ; RF =C2 F5 , n C3 F7 , n C8 F17 ), which enables the direct insertion of CF3 and perfluoroalkyl groups into triazole ring systems. The azidoperfluoroalkanes show good reactivity with terminal alkynes in copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), giving access to rare and stable N-perfluoroalkyl triazoles. Azidoperfluoroalkanes are thermally stable and the efficiency of their preparation should be attractive for discovery programs.

A series of new hypervalent iodine reagents based on the 1,3-dihydro-3,3-dimethyl-1,2-benziodoxole and 1,2-benziodoxol-3-(1H)-one scaffolds, which contain a functionalized tetrafluoroethyl group, have been prepared, characterized, and used in synthetic applications. Their corresponding electrophilic fluoroalkylation reactions with various sulfur, oxygen, phosphorus, and carbon-centered nucleophiles afford products that feature a tetrafluoroethylene unit, which connects two functional moieties. A related λ(3) -iodane that contains a fluorophore was shown to react with a cysteine derivative under mild conditions to give a thiol-tagged product that is stable in the presence of excess thiol. Therefore, these new reagents show a significant potential for applications in chemical biology as tools for fast, irreversible, and selective thiol bioconjugation.

ABSTRACT To further broaden the methods for the heterogeneous phase alkylation of CH acidic compounds, the dialkylation of diethyl ethoxycarbonylmethylphosphonate was studied in the presence of Cs 2 CO 3 under microwave and solvent‐free conditions. It was found that after repeating the alkylations by the addition of newer portions of the alkylating agent and the base on a few occasions, the dialkylation was quite efficient. Even dialkyl derivatives with different alkyl groups could be synthesized. The presence of a phase‐transfer catalyst was harmful, as prevented the formation of the dialkyl products.

The reaction of diethyl ethoxycarbonylmethylphosphonate with a series of alkyl halides, under microwave (MW) and solventless conditions at 120°C, in the presence of Cs 2 CO 3 and in the absence of a phase transfer catalyst afforded the corresponding monoalkylated products in yields of >70%. The thermal variant carried out in boiling acetonitrile was slow and led to incomplete conversions. In the MW method, the phase transfer catalyst is substituted by MW irradiation and there is no need for a solvent. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:241–246, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21009

A variety of reactions including esterifications, alkylations, additions, cycloadditions, fragmentations and condensations were carried out under microwave (MW) and solventless conditions, occasionally in IL-s. In a few cases, the reactions could only be accomplished only under MW conditions, but not on traditional heating. In certain instances, MW could substitute phase transfer catalysis, in other cases MW was synergetic with it.

A variety of reactions including esterifications, alkylations, additions, cycloadditions, fragmentations, and condensations were carried out under microwave MW-assisted and solventless conditions, occasionally in ionic liquids (ILs). In a few cases, MW was synergic with phase transfer catalysis or could substitute it. A variety of P(III) ligands were developed and converted to Pt(II) complexes that can be used as catalysts. Finally, phosphorylations and the Kabachnik-Fields reaction were monitored and optimized by an on-line method, in situ Fourier transform IR spectroscopy.

Optimum conditions for the solid-liquid phase alkylation of methylenebis(diphenylphosphine oxide) (MBDPPO) and ethyl cyanomethylphosphonate (ECMP) were explored studying the role of phase transfer catalysis and microwave (MW) irradiation, as well as the effect of the cation of the alkali carbonate. It was found that the alkylation of MBDPPO may be best accomplished in acetonitrile, in the presence of a quaternary ammonium salt and Cs(2)CO(3), while that of ECMP in the absence of catalyst and solvent using K(2)CO(3). MW irradiation was beneficial in both cases. During the alkylation of ECMP, by-products coming from the alcoholysis of the diethyl ester were also identified. (C) 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:174-179, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20673

Optimum conditions for the solid–liquid phase alkylation of methylenebis(diphenylphosphine oxide) (MBDPPO) and ethyl cyanomethylphosphonate (ECMP) were explored studying the role of phase transfer catalysis and microwave (MW) irradiation, as well as the effect of the cation of the alkali carbonate. It was found that the alkylation of MBDPPO may be best accomplished in acetonitrile, in the presence of a quaternary ammonium salt and Cs CO , while that of ECMP in the absence of catalyst and solvent using K CO . MW irradiation was beneficial in both cases. During the alkylation of ECMP, by-products coming from the alcoholysis of the diethyl ester were also identified. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:174–179, 2011; View this article online at . DOI 10.1002/hc.20673