نتایج جستجو برای: hydrogen halides
تعداد نتایج: 149065 فیلتر نتایج به سال:
Iridium-catalyzed intramolecular [4 + 2] cycloadditions of diene-tethered alkynyl halides were investigated by using [IrCl(cod)](2) as catalyst, and dppe was found to be the most suitable phosphine ligand for the reaction. No oxidative insertion of the iridium into the carbon-halide bond was observed, and the reactions proceeded to provide the halogenated cycloadducts in good yield (75-94%). Th...
This account reviews transition metal-catalyzed C–C bond formation reactions using alkyl halides, which have rarely been used as carbon sources in conventional transition metal-catalyzed systems. In the reactions, ate complexes formed by the reaction of transition metals with a Grignard reagent play important roles as the active catalytic species. The reactions mentioned here are mechanisticall...
[reaction: see text] New air-stable PdCl(2){P(t)Bu(2)(p-R-Ph)}(2) (R = H, NMe(2), CF(3),) complexes represent simple, general, and efficient catalysts for the Suzuki-Miyaura cross-coupling reactions of aryl halides including five-membered heteroaryl halides and heteroatom-substituted six-membered heteroaryl chlorides with a diverse range of arylboronic acids. High product yields (89-99% isolate...
A highly efficient and selective synthesis of (1E)- or (1Z)-1,2-dihalo-1,4-dienes via Pd-catalyzed coupling of haloalkynes and allylic halides is described. The (1E)-1,2-dihalo-1,4-dienes were generated in good yields with excellent stereoselectivities (1E/1Z up to >98/2), while (1Z)-1,2-dihalo-1,4-dienes were produced in excellent yields and stereoselectivities (1Z/1E up to >98/2) by simply ad...
and 9b, were prepared as reported in the ref3). The other pivaloyloxymethyl esters, 9c, 9d and 9e, were prepared via another procedure, which is shown in Scheme 2. Other esters llp~ llw were prepared in the manner similar to that of 9e from the sodium salt of 5e and the corresponding halides. The latter halides were prepared from chloromethyl chlorosulfate (or chloromethyl iodide) and the corre-
The chromium-catalyzed enantioselective addition of carbo halides to carbonyl compounds is an important transformation in organic synthesis. However, the corresponding catalytic enantioselective arylation of ketones has not been reported to date. Herein, we report the first Cr-catalyzed enantioselective addition of aryl halides to both arylaliphatic and aliphatic ketones with high enantioselect...
A highly efficient copper-catalyzed system using commercially available racemic 1,1′-binaphthyl-2,2′-diol (rac-BINOL) as the ligand was eveloped for amination of aryl halides and heteroaryl halides with alkyl amines and N H heterocycles. Good to high yields were obtained for aryl romides and heteroaryl chlorides. The commercially available rac-BINOL ligand with excellent stability and high effi...
A one-pot, convenient method for the preparation of optically active homoallylic alcohols from allyl halides was developed. Allyltrichlorosilanes were generated in situ from allyl halides and trichlorosilane in the presence of cuprous chloride and tertiary amine. Without isolation of the allyltrichlorosilanes, benzaldehyde and chiral biquinoline N,N'-dioxide were introduced into the same flask,...
In this study, a one-pot and efficient method is reported for the synthesis of symmetrical disulfides from alkyl halides in the present of sulfur and 1-butyl-3-methylimidazolium hydroxide as a basic reagent and phase transfer catalyst. The reaction proceeded very fast and afforded the desired products in moderate to excellent isolated yields.
Some N¬-acyl-N'-aryl thiourea derivatives 4(a-f) have been prepared by the reaction of acyl halides ammonium thiocyanate and aryl amines. The structures of synthesized compounds have been characterized by IR, 1HNMR spectral studies. The synthesized compounds 5(a-f) have been screened for antibacterial activity. The effect of the structure of the investigated compounds on the antibacterial activ...
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