نتایج جستجو برای: michlers ketone
تعداد نتایج: 8527 فیلتر نتایج به سال:
[structure: see text] Non-aldol aldol rearrangement of the epoxy silyl ether 13b afforded the expected anti methyl ketone 14, while the diastereomeric epoxy silyl ether 13a afforded the syn methyl ketone 8b via an unprecedented syn hydride migration. Calculations suggest that this unusual reaction proceeds via the carbocation, which cannot easily rotate due to steric hindrance.
The first synthesis of the sesquiterpene Lindenene is described. A novel non-catalysed intramolecular cyclopropanation reaction between a diazoketone and an unactivated alkene was utilised to construct the relatively labile ketone precursor with complete stereocontrol. This ketone was transformed in three steps into Lindenene.
The use of phenyl-2-pyridyl ketone oxime and di-2-pyridyl ketone oxime in Mn chemistry has led to hexanuclear clusters with unprecedented (Mn(II)(4)Mn(III)Mn(IV)) or extremely rare (Mn(II)Mn(III)(5) and Mn(II)(3)Mn(III)(3)) metal oxidation-state combinations and uncommon structural motifs.
A general synthetic approach to the isoprostanes has been established, based on intermolecular aldol condensation of a diazo ketone with an unsaturated aldehyde, followed by cyclization of the resulting diazo ketone to the cyclopropane. Subsequent kinetic opening with thiophenol followed by further elaboration then leads to the isoprostane. The history of this approach and the details of its de...
A new route to luminescent derivatives of androgenic steroids containing a ketone group in the 3- or 17-position has been developed. Reaction with the fac-Re(CO)(3)Cl complex of 3,3'-diamino-2,2'-bipyridine (complex 1) afforded a cyclic aminal product with different steroids. The rate of reaction and yield varies according to the conjugation or steric hindrance around the ketone group.
A series of complexes containing the iron-cyclopentadienone structure were prepared by cyclising bis-propargylic alcohols and their derivatives with iron pentacarbonyl. The resulting complexes were characterised and tested in the catalysis of ketone reduction and alcohol oxidation. The complexes are competent catalysts for ketone reduction and alcohol oxidations.
The first total synthesis of propolisbenzofuran B, a bioactive natural product isolated from honeybee propolis resin, is reported. The convergent synthesis makes use of a silicon-tether controlled oxidative ketone-ketone cross-coupling and a novel benzofuran-generating cascade reaction to deliver the core structure of the natural product from readily prepared precursors.
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