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Showing 1 to 8 of 8 for “"Benzoin Condensation"”.
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Bicyclische Triazoliumsalze als Präkatalysatoren in der asymmetrischen Benzoin- und Acyloinkondensation und asymmetrische Synthese von Oxazolidin-2-onen
… carbene in the asymmetric variant of the benzoin condensation is described. The chiral bicyclic triazolium salt is currently the most efficient precatalyst for the asymmetric benzoin condensation. The substituted acyloins are obtained in moderate to good yields (8 - 83%) and with very good …
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Carbene catalyzed asymmetric nucleophilic acylations with novel triazolium salts
… started to verify their ability to promote the benzoin condensation and intramolecular Stetter reaction. The optimal conditions were identified and allowed for an expansion of the reaction scope with 8-95% yield and enantiomeric excesses of 21-95% in the benzoin condensation. Furthermore, these …
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Neue Heterazoliumsalze aus Prolin und Pyroglutaminsäure und Anwendungen in Carben-katalysierten asymmetrischen nucleophilen Acylierungen
… carbenes in vitro as, for instance, the benzoin condensation, the Stetter and other related nucleophilic acylation reactions have taken their place in the growing field of asymmetric organocatalysis. The synthesis of new carbene catalysts remains an important task aimed at the development …
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Dearomative reduction of arenes through the use of arenophiles & studies towards the synthesis of cardiotonic steroids calotropin and calactin
… strategy which utilizes a NHC-catalyzed benzoin condensation, and Pd-catalyzed nucleophilic dearomatization of a phenol is described. Also described, is the semisynthetic strategy towards calotropin from estrone, where the aromatic A ring is dearomatized to introduce a C1 fragment at the …
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Entwicklung von Carben-katalysierten asymmetrischen intermolekularen Stetter-Reaktionen und direkt gekreuzter intermolekularer Benzoin-Reaktionen
… catalytic cycles. A direct intermolecular cross-benzoin reaction catalyzed by an N-heterocyclic carbene has been developed. The cross-coupling of aromatic aldehydes and trifluoromethyl ketones results in alpha-hydroxy-alpha-trifluoromethyl ketones bearing a quaternary stereocenter with excellent …
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Design and Synthesis of Chiral Triazolium and Thiazolium Salts Incorporating Hydrogen-Bonding Motifs as Organocatalysts
The benzoin condensation is the rst reported example of organocatalysis, and has been studied and used in organic synthesis for over 200 years. Originally catalysed by the cyanide anion, the reaction can also proceed with thiamine as a catalyst. Since then, many N- heterocyclic carbene (NHC) …
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Utilization of Biomass Derived Furans in Value-Added Organics and Heterogeneous Oxorhenium Catalysts for Deoxydehydration of Diols
… oxazoline was studied for the catalytic condensation of diols or epoxides with aldehydes. Here, reactions were done under neat conditions and mild temperatures, achieving good to excellent yields of the 1,3-dioxolane products. The reaction conditions were then applied to the biorenewables …
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Benign Catalysis and Expansion of Cyclobenzoins
Cyclobenzoins are a fledgling class of macrocycles first reported by the Miljanić group in 2015. Since the first reports, several modifications to the original two compounds, cyclotribenzoin and cyclotetrabenzoin, have been reported, but no developments on the production have been reported. Whether …