نتایج جستجو برای: aza cope rearrangement
تعداد نتایج: 64605 فیلتر نتایج به سال:
The synthesis of a homologous series of transoid, bridged sym-oxepin oxides (loa-c) is described. The lower homologues, IOa,b, do not undergo facile Cope rearrangement to the sym-oxepin oxides 15a,b. The generation of transoid 1Oc led rapidly to the production of the Cope rearrangement product 15c. The differing reactivity in the series loa-c is attributed to the inability of lOa,b to interconv...
Tandem deoxygenation-neophyl-type radical rearrangement-electrophile trapping using xanthates from 7-azabenzonorbornadienes gives 3-exo-substituted 2-aza-5,6-benzonorbornenes, which in some cases undergo isomerisation to (aminomethyl)indenes. The starting xanthates are accessible in good yields and high enantiomeric ratios via asymmetric hydroboration of (aryne/pyrrole-derived) 7-azabenzonorbor...
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.
BACKGROUND Asymmetric introduction of fluorine alpha-to a carbonyl has become popular recently, largely because the direct fluorination of enolates by asymmetric electrophilic fluorinating reagents has improved, and as a result such compounds are becoming attractive synthons. We have sought an alternative but straightforward asymmetric method to this class of compounds, utilising the zwitterion...
Microwave irradiation of chloroacetylarenes and enamines induced an aza-Darzens reaction followed by rearrangement of the aziridinium intermediate to give (2-amino-3-alkenoyl)arenes that were reduced selectively to syn-beta-aminoalcohols as pseudo-ephedrine analogues.
This article describes the aza-Piancatelli rearrangement with hydroxylamines to 4-aminocyclopentenones and subsequent transformations that highlight the versatility of the cyclopentene scaffold and the value of the hydroxylamine nucleophile in this transformation.
The Meyer-Schuster rearrangement is an efficient method to prepare ?,?-unsatured carbonyl compounds starting from propargylic alcohols and this review presents the remarkable progress made during last decade in reaction. New catalytic systems have been discovered many elegant applications reported for rearrangement. To be noticed particular are new cascade processes affording a wide range of ca...
As the basis and preliminary work of future experimental study on PAHs formation under high temperature, theoretical computations on the intramolecular rearrangement reactions of sylvestrene (1-methyl-3-vinylcyclohexene) and 1,4-dimethyl-4-vinylcyclohexene are conducted and reveal that they may be transformed to themselves. The conversion between Dipentene and 2,4-dimethyl-4-vinylcyclohexen...
The secondary ent-beyeran-16-yl carbocation (7) is a key branch point intermediate in mechanistic schemes to rationalize the cyclic structures of many tetra- and pentacyclic diterpenes, including ent-beyerene, ent-kaurene, ent-trachylobane, and ent-atiserene, presumed precursors to >1000 known diterpenes. To evaluate these mechanistic hypotheses, we synthesized the heterocyclic analogues 16-aza...
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