نتایج جستجو برای: substutuent effect claisen rearrangement
تعداد نتایج: 1667083 فیلتر نتایج به سال:
Efficient syntheses are described for the synthetically important 3-methylquinoline-4-carbaldehydes 6a-h from o-nitrobenzaldehydes 1a-h employing a Wittig-olefination-Claisen-rearrangement protocol. The Wittig reaction of o-nitrobenzaldehydes with crotyloxymethylene triphenylphosphorane afforded crotyl vinyl ethers 2a-h, which on heating under reflux in xylene underwent Claisen rearrangement to...
A stereoselective synthesis of (+)-physoperuvine, a tropane alkaloid from Physalis peruviana Linne has been developed using a one-pot tandem aza-Claisen rearrangement and ring closing metathesis reaction to form the key amino-substituted cycloheptene ring.
The first total synthesis of the proposed structure of astakolactin, a sesterterpene metabolite isolated from the marine sponge Cacospongia scalaris, has been achieved, mainly featuring Johnson-Claisen rearrangement, asymmetric Mukaiyama aldol reaction and MNBA-mediated lactonization.
The first asymmetric total synthesis of psychotrimine, a trimeric indole alkaloid, was accomplished via an asymmetric Ireland-Claisen rearrangement to construct a chiral quaternary carbon center, thereby establishing the absolute configuration of psychotrimine.
Abstract Polarized alkynes such as ynol ethers and ynamides have attracted much attention due to their inherent unique reactivity. Herein, we report Au(I)-catalyzed hydroalkoxylation/Claisen rearrangement cascade reactions of aryl with allylic alcohols. At the first stage (hydroalkoxylation) this reaction, attack alcohols or occurs at ?-position polarized in a completely regioselective manner. ...
The total synthesis of CBD-C4 (cannabidibutol) is reported. enantioselective based on a) the use 3,5-dimetoxybenzaldehyde as starting material, b) Corey-Bakshi-Shibata reduction, c) Claisen-Ireland rearrangement, d) ring-closing metathesis, and e) not-trivial demethylation induced by sodium ethanethiolate.
An enantioselective total synthesis of the diterpenoid natural product (+)-salvileucalin B is reported. Key findings include a copper-catalyzed arene cyclopropanation reaction to provide the unusual norcaradiene core and a reversible retro-Claisen rearrangement of a highly functionalized norcaradiene intermediate.
Kinetic investigations of substituent effects in the thermal rearrangement of bis-vinyl ether substrates are reported. Findings indicate that the influence of the various substituent patterns on the rate of rearrangement in these compounds differs from that documented in the literature for the analogous [3,3]-sigmatropic rearrangement of allyl vinyl ethers. In addition, the thermochemical data ...
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