Prins Cyclization Catalyzed by a FeIII/Trimethylsilyl Halide System: The Oxocarbenium Ion Pathway versus the [2+2] Cycloaddition
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چکیده
منابع مشابه
Iodine-catalyzed prins cyclization of homoallylic alcohols and aldehydes.
The iodine-catalyzed Prins cyclization of homoallylic alcohols and aldehydes was investigated under metal-free conditions and without additives. Anhydrous conditions and inert atmosphere are not required. The reaction of 2-(3,4-dihydronaphthalen-1-yl)propan-1-ol and 21 aldehydes (aliphatic and aromatic) in CH₂Cl₂ in the presence of 5 mol % of iodine gave 1,4,5,6-tetrahydro-2H-benzo[f]isochromen...
متن کاملIodine-Catalyzed Prins Cyclization of Aliphatic and Aromatic Ketones
A ciclização de Prins catalisada por iodo entre álcoois homoalílicos e cetonas foi investigada. Condições anidras e atmosfera inerte não são necessárias neste protocolo ausente de metais. A reação do 2-(3,4-di-hidronaftalen-1-il)propan-1-ol com seis cetonas simétricas alifáticas levou ao produto desejado em 67-77% de rendimento. A ciclização foi realizada com quatro cetonas alifáticas assimétri...
متن کاملEnabling New Modes of Reactivity via Constrictive Binding in a Supramolecular-Assembly-Catalyzed Aza-Prins Cyclization.
Supramolecular assembly 1 catalyzes a bimolecular aza-Prins cyclization featuring an unexpected transannular 1,5-hydride transfer. This reaction pathway, which is promoted by constrictive binding within the supramolecular cavity of 1, is kinetically disfavored in the absence of 1, as evidenced by the orthogonal reactivity observed in bulk solution. Mechanistic investigation through kinetic anal...
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Condensation of an aldehyde with an α-amino-ester, followed by a tandem process involving cyclization to a seven-membered ring, deprotonation to an intermediate azomethine ylide and intramolecular dipolar cycloaddition gave tricyclic products related to stenine and neostenine.
متن کاملEnantioselective thiourea-catalyzed additions to oxocarbenium ions.
Asymmetric, catalytic reactions of oxocarbenium ions are reported. Simple, chiral urea and thiourea derivatives are shown to catalyze the enantioselective substitution of silyl ketene acetals onto 1-chloroisochromans. A mechanism involving anion binding by the chiral catalyst to generate a reactive oxocarbenium ion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest en...
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ژورنال
عنوان ژورنال: Chemistry - A European Journal
سال: 2015
ISSN: 0947-6539
DOI: 10.1002/chem.201502488