Friedel-CraftsType Arylation Strategy for the Conversion of Alkyl 2-((Diphenoxyphosphoryl)oxy)-2-arylacetates to α,α-Diaryl Esters.

An arylation strategy allowing the conversion of alkyl 2-((diphenoxyphosphoryl)oxy)-2-arylacetates to α,α-diaryl esters is reported. This transformation can be promoted by TfOH when the starting organic phosphates do not carry -alkoxy groups on their aryl rings, but it does not require any additives when such groups are present. These alkyl 2-((diphenoxyphosphoryl)oxy)-2-arylacetates can be readily accessed from the insertion of diphenyl phosphate into aryldiazoacetates.

An -Robinson Annulation Strategy for the Synthesis of Fused Bicyclic Amides: Synthesis of (±)-Coniceine and Quinolizidine.

An -Robinson annulation strategy is described using a NaOEt-catalyzed conjugate addition of cyclic imides onto vinyl ketones, followed by a TfOH-mediated intramolecular aldol condensation to afford densely functionalized fused bicyclic amides. The potential use of these amides in the synthesis of alkaloids is demonstrated by the sequential conversion of appropriate precursors to (±)-coniceine and quinolizidine in two additional steps, thus allowing their preparation in overall 40 and 44% yields, respectively.

Visible light-mediated photolysis of organic molecules: the case study of diazo compounds.

Considering the recent rapid advancement of synthetic technologies promoted by visible light in the last 15 years, the use of photocatalysts has been rightfully justified based on the fact that organic molecules generally do not absorb visible light. However, an increasing number of different classes of organic molecules is being identified as actually directly absorbing in this region of the electromagnetic spectrum. Among them, diazo compounds are possibly one of these classes whose chemistry has been more explored so far.

Synthesis of 4-(organoselenyl) oxazolones cyclization of -alkynyl ethylcarbamates promoted by organoselenium.

Organoselenyl iodide promoted the intramolecular nucleophilic cyclization of -alkynyl ethylcarbamates in the synthesis of 4-(organoselenyl) oxazolones. The reaction was regioselective, giving the five-membered oxazolone products as the unique regioisomer an initial activation of the carbon-carbon triple bond through a seleniranium intermediate, followed by an intramolecular 5- cyclization mode. The generality of the methodology has been proven by applying the optimized reaction conditions to different organoselenyl iodides and -alkynyl ethylcarbamates having different substituents directly bonded to the nitrogen atom and in the terminal position of the alkyne.

Palladium-Catalyzed Cascade 5--dig Cyclization of Ynamides to Form 4-Alkynyloxazolones.

The selective synthesis of 4-alkynyloxazolones and their further applications as substrates to electrophile-promoted nucleophilic cyclization have been developed. The reaction of ynamides with terminal alkynes proceeded smoothly to give 4-alkynyloxazolones in the presence of a catalytic amount of palladium(II) acetate. The products were obtained with the sequential formation of new C-C and C-O bonds via a cascade procedure.

Diorganyl Diselenides and Iron(III) Chloride Drive the Regio- and Stereoselectivity in the Selenation of Ynamides.

We report here our results on the application of ynamides as substrates in the reactions with diorganyl dichalcogenides and iron(III) chloride to give selectively three different types of compounds: -α-chloro-β-(organoselenyl)enamides, 4-(organochalcogenyl)oxazolones, and vinyl tosylates. The results reveal that the selectivity in the formation of products was obtained by controlling the functional groups directly bonded to the nitrogen atom of the ynamides. Thus, α-chloro-β-(organoselenyl) enamide derivatives were exclusively obtained when the Ts- and Ms-ynamides were treated with a mixture of diorganyl diselenides (1.

Similar hepatoprotective effectiveness of Diphenyl diselenide and Ebselen against cisplatin-induced disruption of metabolic homeostasis and redox balance in juvenile rats.

Cisplatin is an antineoplastic drug well recognized for its success in the battle against several types of cancer in adult, juvenile, and child populations. Meanwhile, this drug is also famous due to its serious side effects, such as hepatotoxicity. This study evaluated the hepatoprotective effectiveness of Diphenyl Diselenide (PhSe) and Ebselen in a model of cisplatin-induced toxicity in juvenile rats.

Cyclization of Thiopropargyl Benzimidazoles by Combining Iron(III) Chloride and Diorganyl Diselenides.

A practical synthetic approach to the synthesis of 3-(organoselenyl)-imidazothiazines was developed. The methodology involved the regioselective 6-endo-dig cyclization of thiopropargyl benzimidazoles promoted by diorganyl diselenides and iron(III) chloride. The investigation to determine the best reaction conditions indicated the use of thiopropargyl benzimidazoles (0.

Iron(III) chloride and diorganyl diselenides-mediated 6-endo-dig cyclization of arylpropiolates and arylpropiolamides leading to 3-organoselenyl-2H-coumarins and 3-organoselenyl-quinolinones.

Combination of iron(III) chloride and diorganyl diselenides was used for cyclization of arylpropiolates and arylpropiolamides in formation of 3-organoselenyl-2H-coumarins and 3-organoselenyl-quinolinones, respectively. Systematic study to determine the ideal conditions revealed that the two substrates reacted in the same way using identical reaction conditions. The versatility of this method has been demonstrated by extension of the best reaction conditions to substrate having a variety of substituents.

Synthesis of pyridazinones through the copper(I)-catalyzed multicomponent reaction of aldehydes, hydrazines, and alkynylesters.

The copper-catalyzed multicomponent cyclization reaction, which combined aldehydes, hydrazines, and alkynylesters, was applied in the synthesis of pyridazinones. The reaction was regioselective and gave only six-membered pyridazinones in the complete absence of five-membered pyrazoles or a regioisomeric mixture. During this investigation, the use of 2-halobenzaldehyde as the starting material, under identical reaction conditions, gave 6-(2-ethoxyphenyl)pyridazinones after sequential Michael addition/1,2-addition/Ullmann cross-coupling reactions.