RESUMEN
A distinctive N-substituent-controlled regioselective 1,4-hydrocarbonation or 1,4-hydrocarbonation/5-endo-trig cyclization cascade reaction of ß-CF3-1,3-enynamides with ß-dicarbonyl compounds in the presence of a simple base is reported. ß-CF3-1,3-enynamides having a Ts group N-substituent produce γ-CF3-allenamides via a 1,4-hydrocarbonation process, whereas ß-CF3-1,3-enynamides bearing a Ms group N-substituent lead to 3-CF3-cyclopentenylamines through a 1,4-hydrocarbonation/5-endo-trig cyclization cascade process.
RESUMEN
A new metal-free method for the rapid, productive, and scalable preparation of 3-trifluoromethyl pyrroles has been developed. It is based on the electrophilic nature of the double bond of ß-CF3-1,3-enynamides due to the electron-withdrawing characteristics of the trifluoromethyl groups and the strong nucleophilic nature of alkyl primary amines. Evidence for the highly regioselective 1,4-hydroamination was observed after the isolation and characterization of the allenamide intermediate.
RESUMEN
Chiral perhydroindoles are found in a number of natural products and biologically active compounds. Therefore, the development of new asymmetric methodology for rapid access to this core is of high importance. Herein, we reported a highly regio- and diastereo-selective palladium/PC-Phos-catalyzed asymmetric Heck/Tsuji-Trost reactions of readily available amino tethered 1,3-cyclohexadienes with aryl and alkenyl halides, delivering various functionalized chiral hexahydroindoles in good yields with high enantioselectivity. The application of this reaction to the concise synthesis of (-)-α-Lycorane was demonstrated. DFT computation results indicate that the difference in ΔEdis of two migration insertion transition states determines the enantioselectivity of the reaction.
Asunto(s)
Ciclohexenos , Paladio , Estructura Molecular , CatálisisRESUMEN
The development of diversity-oriented synthesis based on fluorine-containing building blocks has been one of the hot research fields in fluorine chemistry. ß-CF3-1,3-enynes, as one type of fluorine-containing building blocks, have attracted more attention in the last few years due to their distinct reactivity. Numerous value-added trifluoromethylated or non-fluorinated compounds which have biologically relevant structural motifs, such as O-, N-, and S-heterocycles, carboncycles, fused polycycles, and multifunctionalized allenes were synthesized from these fluorine-containing building blocks. This review summarizes the most significant developments in the area of synthesis of organofluorine compounds based on ß-CF3-1,3-enynes, providing a detailed overview of the current state of the art.
Asunto(s)
Flúor , Flúor/química , EstereoisomerismoRESUMEN
The divergent regioselective cyclization of N-(2-trifluoromethyl-3-alkynyl) oximes by a suitable choice of a gold(i) or a Brønsted acid catalyst, leading to 4-trifluoromethyl-N-hydroxypyrroles or 4-trifluoromethyl-5-alkylisoxazoles was developed. In order to avoid the tedious separation of unstable N-(2-trifluoromethyl-3-alkynyl) oximes, an easy two-step, one-pot synthesis of 4-trifluoromethyl-5-alkylisoxazoles was realized via the sequential oxidation of the corresponding hydroxylamines and subsequent treatment with the reductant, sodium thiosulfate (Na2S2O3). This two-step, one-pot procedure is a complementary method for the synthesis of 4-trifluoromethyl-5-alkylisoxazole from those unstable N-(2-trifluoromethyl-3-alkynyl) oximes.
RESUMEN
A simple base mediated reaction of 2-trifluoromethyl-1,3-conjugated enynes with N-acetylated 2-aminomalonates was developed, which could deliver two distinct types of products depending on substrates, i.e. 4-trifluoromethyl pyrrolidine derivatives, or gem-difluoro-1,3-conjugated enyne derivatives. Various functionalized 4-(difluoromethylene)-1,2,3,4-tetrahydropyridines could be obtained in good yields via the gold(i)-catalysed 6-endo-dig cyclization of the corresponding gem-difluoro-1,3-conjugated enynes under mild conditions.
RESUMEN
A novel NIS-mediated oxidative cyclization of N-(2-trifluoromethyl-3-alkynyl)hydroxylamines is developed, which provides a facile access to 4-trifluoromethyl-5-acylisoxazoles in 33-91% yields. Various types of commonly used electrophilic halogen source such as ICl, I2, NIS, NBS and NCS at different temperatures in various solvents were investigated. It was found that the NIS acts as both an oxidant and an electrophile for the present sequential transformation. The scope, mechanism and application of this NIS-mediated domino reaction for further synthetic transformation were studied.
RESUMEN
What a ring formation! Bicyclic dihydropyrrolizines with an electron-withdrawing group (EWG) at the 5-position are formed in one step from linear azidoenynes under gold catalysis. This novel route involves the use of azide as a nitrene precursor, electronically-controlled regioselectivity, and the generation of destabilized 1-azapentadienium ions and their pericyclic reactions. This method was used for a formal synthesis of 7-methoxymitosene.
Asunto(s)
Antibacterianos/síntesis química , Oro/química , Mitomicinas/síntesis química , Pirroles/síntesis química , Antibacterianos/química , Catálisis , Química Farmacéutica , Mitomicinas/química , Estructura Molecular , Pirroles/química , EstereoisomerismoRESUMEN
A chemodivergent tandem intermolecular hydrocarbonation and intramolecular oxy- or thioheterocyclization sequence of ß-CF3-1,3-enyne with ß-ketothioamides (KTAs) leading to ring-trifluoromethylated 4H-pyran or 4H-thiopyran, respectively, by the combined use of AgNO3 as a catalyst and Et3N as a base was developed. A remarkable substituent effect was observed. The substituent on either the keto moiety or the nitrogen atom of ß-ketothioamides has a great impact on the chemoselectivity. Enynes possessing electron-withdrawing aryl groups on the alkyne moiety are generally good candidates for the present transformation.
RESUMEN
Excess iron accumulation occurs in organs of patients with certain genetic disorders or after repeated transfusions. No physiological mechanism is available to excrete excess iron and iron overload to promote lipid peroxidation to induce ferroptosis, thus iron chelation becomes critical for preventing ion toxicity in these patients. To date, several iron chelators have been approved for iron chelation therapy, such as deferiprone and deferoxamine, but the current iron chelators suffer from significant limitations. In this context, new agents are continuously sought. Here, a library of new deferric amine compounds (DFAs) with adjustable skeleton and flexibility is synthesized by adopting the beneficial properties of conventional chelators. After careful evaluations, compound DFA1 is found to have greater efficacy in binding iron through two molecular oxygens in the phenolic hydroxyl group and the nitrogen atom in the amine with a 2:1 stoichiometry. This compound remarkably ameliorates iron overload in diverse murine models through both oral and intravenous administration, including hemochromatosis, high iron diet-induced, and iron dextran-stimulated iron accumulation. Strikingly, this compound is found to suppress iron-induced ferroptosis by modulating the intracellular signaling that drives lipid peroxidation. This study opens a new approach for the development of iron chelators to treat iron overload.
Asunto(s)
Ferroptosis , Hemocromatosis , Sobrecarga de Hierro , Aminas , Animales , Deferiprona , Deferoxamina/farmacología , Deferoxamina/uso terapéutico , Dextranos , Humanos , Hierro/metabolismo , Quelantes del Hierro/farmacología , Quelantes del Hierro/uso terapéutico , Sobrecarga de Hierro/tratamiento farmacológico , Ratones , Nitrógeno , Piridonas/farmacología , Piridonas/uso terapéuticoRESUMEN
Three types of trifluoromethylated pyrazolidines, pyrazolines, and pyrazoles can be synthesized via divergent reaction of ß-CF3-1, 3-enyne with hydrazines. The reaction with simple hydrazine monohydrate or sulfonyl hydrazines as nucleophiles produces 1,3,4-trisubstituted pyrazolines, whereas the reaction with acetyl hydrazine as nucleophiles affords 1,4,5-trisubstituted pyrazolidines. Using phenylhydrazine or tert-butylhydrazine as a reaction partner, the products are easily oxidized to form 1,4,5-trisubstituted pyrazoles.
RESUMEN
Herein, we described an efficient copper-catalyzed chemo-divergent tandem reaction of N-(ortho-alkynyl)aryl-pyrrole and (iso)indoles, delivering ring-fused N-heterocycles in good yields in an atom-economical manner. N-(ortho-alkynyl)aryl-pyrrole and indoles undergo the tandem cyclization/migration reaction, in which the group at 2-position was migrated to 3-position. In contrast, the dearomative cyclization of N-(ortho-alkynyl)aryl-isoindoles would occur to deliver the N-fused tetracyclic products efficiently.
RESUMEN
Efficient route: A novel Rh(I)-catalyzed regio- and stereospecific carbonylation reaction of (1-alkynyl)cyclopropyl ketones by selective activation of a carbon-carbon sigma bond of the cyclopropane ring was demonstrated (see scheme). This method provides a general, efficient, stereoselective route to synthesise 1,3,5-trisubstituted and 1,3,5,6-tetrasubstituted 5,6-dihydrocyclopenta[c]furan-4-one with convertible functional groups.
Asunto(s)
Furanos/química , Rodio/química , Catálisis , Ciclización , Cetonas/química , Modelos Moleculares , Estructura Molecular , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
The DBU-catalyzed reaction of 1-(1-alkynyl)-2-alken-1-ones with 1,3-dicarbonyl compounds produces 4H-pyrans in moderate to excellent yield, whereas the cationic Pd(ii)-catalyzed reaction affords furans regioselectively.
RESUMEN
A divergent synthesis of thioether-functionalized trifluoromethyl-alkynes, 1,3-dienes and allenes via regioselective nucleophilic addition of sulfur nucleophiles to 2-trifluoromethyl-1,3-conjugated enynes was developed. The addition patterns depend on the type of enyne, sulfur nucleophile and reaction conditions used. 1,4-Addition leading to thioether-functionalized trifluoromethyl-allenes was realized when enynes possessing electron-withdrawing aryl groups on the alkyne moiety were used as reaction partners and alkanethiols were used as nucleophiles, whereas solvent-controlled construction of thioether-functionalized 1,3-dienes and alkynes was realized, respectively, via a 3,4-addition pattern or 1,2-addition pattern if thiophenols were applied as nucleophiles. The three types of compounds containing both sulfur and fluorine elements are valuable building blocks for synthesis of multifunctional fluorinated vinyl sulfides and thiophene derivatives.
RESUMEN
A highly efficient tandem hydroamination and cyclization reaction of 2-trifluoromethyl-1,3-enynes with primary amines leading to 4-trifluoromethyl-3-pyrrolines was developed by using AgNO3 as a catalyst under mild reaction conditions. This new method is compatible with alkyl, aryl, and allyl primary amines, representing an atom-economical protocol for the construction of 4-trifluoromethyl-3-pyrrolines for the first time.
RESUMEN
An easy two-step, one-pot synthesis of halogenated trifluoromethylated pyrroles is realized by sequential intermolecular hydroamination reaction of 2-trifluoromethyl-1,3-enynes with aliphatic primary amines under mild reaction conditions, and NXS mediated oxidative cyclization of the hydroamination product. The salient features of this method include mild conditions, readily available starting materials, general substrate scope, high efficiency and synthetic utility of the products.
RESUMEN
A simple base-mediated tandem SN2'/SNV reaction of the readily available α-trifluoromethyl-α,ß-unsaturated carbonyl compounds with N-tosylated 2-aminomalonates was developed, which provide an efficient access to functionalized tetrasubstituted 2-fluoro-2-pyrrolines in good to excellent yields. In contrast, simple 1,2-nucleophilic adducts were produced when α-trifluoromethyl styrenes were used.
Asunto(s)
Cetonas/química , Malonatos/química , Pirroles/síntesis químicaRESUMEN
A straightforward and efficient approach to structurally diverse and synthetically useful ring-fluorinated 4H-pyrans via a simple base-mediated cascade reaction of readily available trifluoromethylated alkenes with 1,3-dicarbonyl compounds was developed. The key events of this reaction involve two consecutive C-F substitutions under very mild conditions.
RESUMEN
The IPrAuNTf2/HNTf2 co-catalyzed cyclization of N-(2-perfluoroalkyl-3-alkynyl) hydroxylamines produces pyrroles in moderate to excellent yield, whereas the AgOTf-catalyzed reaction affords cyclic nitrones in high yields.