نتایج جستجو برای: aza cope rearrangement
تعداد نتایج: 64605 فیلتر نتایج به سال:
The doubly diastereoselective [3,3]-sigmatropic aza-Claisen rearrangement of silylketene aminals derived from 5-substituted (3S,4E,alphaR)-1-benzyloxy-3-[N-acyl-N-(alpha-methylbenzyl)amino]pent-4-enes furnishes 2,3-disubstituted (R)-N-alpha-methylbenzyl (2S,3R,4E)-7-benzyloxyhept-4-enamides in >90% de under the "matched" control of both stereogenic centres. Rearrangement of the "mismatched" dia...
On thermolysis appropriately substituted N-silyloxy-N-allyl enamines undergo smooth 3,3-sigmatropic rearrangments to the corresponding N-silyloxy imino ethers.
Reaction between 1,2-bis(2-hydroxyphenyl)-ethylenediamine (hpen) and methyl pyruvate gives the diaza-Cope rearrangement product with good yield and excellent stereospecificity. The product containing two chiral quaternary carbon centers is characterized by high performance liquid chromatography and X-ray crystallography. DFT computation provides insight into why the diaza-Cope rearrangement tak...
An efficient palladium-catalyzed asymmetric hydrogenation via capture of an active intermediate generated in situ from acid-catalyzed aza-Pinacol rearrangement has been successfully developed, providing efficient access to chiral exocyclic amines with up to 98% ee. Three-, four-, and five-membered cyclic N-sulfonyl amino alcohols are viable substrates. This study opens a new window to the appli...
The observed rate of reaction in the dysprosium triflate catalyzed aza-Piancatelli rearrangement is controlled by a key off-cycle binding between aniline and catalyst. Deconvoluting the role of these ancillary species greatly broadens our understanding of factors affecting the productive catalytic pathway. We demonstrate that the rate of reaction is controlled by initial competitive binding bet...
The Claisen rearrangement and its applications to organic synthesis have been studied for a long time.l In recent years, this rearrangement has been applied in stereocontrolled natural product synthesis2 and asymmetric i n d ~ c t i o n . ~ The term "Claisen rearrangement", which originally denoted the rearrangement of allyl aryl ethers to 0or p-allylphenols, has now been extended to analogous ...
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