نتایج جستجو برای: alkyl halides
تعداد نتایج: 17469 فیلتر نتایج به سال:
A versatile heterogeneous photocatalysis protocol was developed by using ruthenium bipyridyl tethered porous organosilica (Ru-POS). The versatility of the Ru-POS catalyst in organo-photocatalysis was explored by (i) oxidative aromatization of Hantzsch ester, (ii) reductive dehalogenation of alkyl halides, and (iii) functional group interconversion (FGI) of alcohols to alkyl halides.
Non-activated alkyl halides are challenging substrates for cross-coupling reactions because they are reluctant to undergo oxidative addition and because metal alkyl intermediates are prone to beta-H elimination. Despite recent progress, well-defined catalysts are rare. We recently prepared Ni complexes with a chelating pincer-type bis(amino)amide ligand. The chloride complex [((Me)NN2)NiCl] is ...
We report a new class of catalytic reaction: the thermal substitution of a secondary and or tertiary alkyl halide with a nitrogen nucleophile. The alkylation of a nitrogen nucleophile with an alkyl halide is a classical method for the construction of C-N bonds, but traditional substitution reactions are challenging to achieve with a secondary and or tertiary alkyl electrophile due to competing ...
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...
This scheme has been used to explain qualitatively that neither alkyl halides yielding very unstable (i. e. reactive) wbenium ions nor alkyl halides yielding very stable (i. e. unreactive) carbenium ions are efficient initiators. In the fiist case step (1) and in the second case step (2) is unfav~rable~.~). Other authors criticized this conclusion and offered alternative interpretations for the...
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.
A catalytic asymmetric alkylation of fully substituted enolates with racemic, non-activated secondary alkyl halides is described. The chiral 1,2,3-triazolium ion enables excellent diastereo- and enantiocontrol via enantiofacial discrimination of prochiral enolates and kinetic resolution of secondary halides.
The mechanism of reductive cleavage of model alkyl halides (methyl 2-bromoisobutyrate, methyl 2-bromopropionate, and 1-bromo-1-chloroethane), used as initiators in living radical polymerization (LRP), has been investigated in acetonitrile using both experimental and computational methods. Both theoretical and experimental investigations have revealed that dissociative electron transfer to these...
Within the last decades the transition metal-catalyzed cross-coupling of non-activated alkyl halides has significantly progressed. Within the context of alkyl-alkyl cross-coupling first row transition metals spanning from iron, over cobalt, nickel, to copper have been successfully applied to catalyze this difficult reaction. The mechanistic understanding of these reactions is still in its infan...
Within the last decades the transition metal-catalyzed cross-coupling of non-activated alkyl halides has significantly progressed. Within the context of alkyl-alkyl cross-coupling, first row transition metals spanning from iron, over cobalt, nickel, to copper have been successfully applied to catalyze this difficult reaction. The mechanistic understanding of these reactions is still in its infa...
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