نتایج جستجو برای: 1 2 diketones
تعداد نتایج: 3934068 فیلتر نتایج به سال:
Acylation reaction of a variety of cyclic ketones via acylation of the corresponding enamines is welldefined in the literature. Enamine acylation of carbonyl compounds is a significant synthetic method because of its mildness and the ease of preparing various β-diketones [1-4]. Acylation reactions are performed by means of converting enamines to the enaminoketones and subsequent hydrolysis of t...
A pyridine-catalyzed ylide cyclization affording dihydrofurans and dihydropyrroles has been developed. In the presence of a catalytic amount of pyridine and Fe(Tcpp)Cl, α-ylidene-β-diketones and α,β-unsaturated imines react with diazoacetates providing dihydrofurans and dihydropyrroles respectively, in up to 96% yield with high diastereoselectivities.
Gold-catalyzed O-vinylation of cyclic 1,3-diketones has been achieved for the first time, which provides direct access to various vinyl ethers. A catalytic amount of copper triflate was identified as the significant additive in promoting this transformation. Both aromatic and aliphatic alkynes are suitable substrates with good to excellent yields.
The organocatalytic Michael addition of malonates to symmetric unsaturated 1,4-diketones catalyzed by thiourea and squaramide derivatives with Cinchona alkaloids afforded the formation of a new C-C bond in high yields (up to 98%) and enantiomeric purities (up to 93%). The absolute configuration of the product was suggested from comparison of the experimental and calculated VCD spectra of the re...
Different synthetic routes leading to terpyridines functionalised with furan heterocycles are reviewed. The methodologies used to prepare such compounds include the ring closure of 1,5-diketones and cross-coupling reactions. These versatile terpyridines and their derived metal complexes find applications in various fields including coordination chemistry, medicinal chemistry and material sciences.
The photodynamics in symmetric and unsymmetric β-diketones are studied with transient absorption in the deep-UV. Excitation leads to ultrafast ESIPT while further relaxation and isomerization processes depend on the molecular symmetry and solvent environment. OCIS codes: (320.7150) Ultrafast spectroscopy; (300.6540) Spectroscopy, ultraviolet; (190.7110) Ultrafast nonlinear optics
Ambiphilic allenes are generated by an organocatalyzed domino reaction of alkyl propiolates and aromatic 1,2-diketones; in the absence of any external chemical agent, these allenes perform a thermally-driven dimerization reaction to generate the corresponding fully-substituted cyclobutanes in a regio- and highly stereoselective manner.
The air and moisture stable fluoroiodane 8, readily prepared on a 6 g scale by nucleophilic fluorination of the hydroxyiodane 7 with TREAT-HF, has been used as an electrophilic fluorinating reagent for the first time to monofluorinate 1,3-ketoesters and difluorinate 1,3-diketones in good isolated yields.
The asymmetric intermolecular Stetter reaction is catalyzed by a novel triazolium salt derived N-heterocyclic carbene leading to 1,4-diketones in moderate to excellent yields (49-98%) and moderate to good enantioselectivities (56-78% ee), which could be enhanced by one recrystallization to excellent levels (90-99% ee).
1,2-diketones have been reacted in one-pot method with 1,2-diamines at room temperature with zno nanoparticles as a catalyst. zno nanoparticles as an available and reusable catalyst is used for the synthesis of quinoxalinein improved yields.
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