منابع مشابه
Quantum chemical characterization of cycloaddition reactions between 1,3-butadiene and oxyallyl cations of varying electrophilicity†
Hydroxyallyl cation and lithium and sodium oxyallyl cations are predicted to react with 1,3-butadiene both in a stepwise fashion and via concerted [4 3] cycloaddition with so-called extended stereochemistry. With hydroxyallyl cation, the stepwise process is preferred and subsequent second bond closures generate products equivalent to those that would arise from concerted [4 3] or [3 2] cyclo...
متن کاملA catalytic dipolar cycloaddition route to pyrroloimidazoles
A catalytic method involving carbenoid insertion onto dihydroimidazoles is reported for the generation of dihydroimidazolium ylides, and their subsequent diastereoselective cycloaddition to form pyrrolo[1,2-a]imidazoles © 2009 Elsevier Science. All rights reserved ———
متن کاملPalladium-catalyzed [3 + 2] intramolecular cycloaddition of alk-5-enylidenecyclopropanes.
Readily accessible alk-5-enylidenecyclopropanes undergo [3 + 2] intramolecular cycloaddition reactions upon treatment with appropriate palladium complexes. The method allows the rapid and efficient assembly of a variety of bicyclo[3.3.0]octane systems with up to three stereocenters. Preliminary theoretical calculations uncovered previously unsuspected mechanistic possibilities based on either a...
متن کاملNanocontact-induced catalytic activation in palladium nanoparticles.
We report the synthesis and catalytic studies of novel palladium nanostructures assembled from small nanoparticles by a surfactant-templated method. These one-dimensional nanomaterials comprise high-density nanocontacts of approximately 1 nm in contact length at the particle-particle interface. In contrast to dispersed Pd nanoparticles ( approximately 5 nm), the polycrystalline palladium nanowi...
متن کاملHexachloroacetone as a precursor for a tetrachloro-substituted oxyallyl intermediate: [4+3] cycloaddition to cyclic 1,3-dienes.
The enol phosphate 2,2-dichloro-1-(trichloromethyl)ethenyl diethyl phosphate (1), easily available by a Perkow reaction between hexachloroacetone and triethyl phosphite, reacts with sodium trifluoroethoxide/trifluoroethanol in the presence of cyclic 5-membered 1,3-dienes to furnish alpha,alpha,alpha',alpha'-tetrachloro-substituted[3.2.1]bicyclic ketones 2. A [4+3] cycloaddition of a tetrachloro...
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ژورنال
عنوان ژورنال: Science
سال: 2018
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.aau4821