- SmI2-promoted intra- and intermolecular C-C bond formation with chiral N-acyl oxazolidinones
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The suitability of chiral oxazolidinones in the SmI2-mediated C-C bond generation between the imide functionality of an N-acyl oxazolidinone unit and an olefinic radical acceptor, in both inter- and intramolecular reactions, was investigated. It was shown that the products from an Evans asymmetric alkylation can undergo direct carbon-carbon bond formation with an acrylamide providing chiral acyclic ketones in reasonable yields. These examples represent the first transformation of such N-acyl oxazolidinones where this chiral auxiliary is removed under the conditions for ketone formation. 5-exo-trig Cyclization studies were also undertaken with the same type of substrates, providing trans-2,5-disubstituted cyclopentanones in yields of approx. 50%. However, attempts to cyclize heteroatom-containing equivalents were less rewarding.
- Taaning, Rolf H.,Thim, Laura,Karaffa, Jacob,Campa?a, Araceli G.,Hansen, Anna-Mette,Skrydstrup, Troels
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experimental part
p. 11884 - 11895
(2009/04/07)
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- The preparation and reaction of enolates within micro reactors
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Over the past 5 years, interest in the miniaturisation of chemical synthesis has grown rapidly, however in order to facilitate transfer of the technology from its current position as a research tool to industrial applications, a core understanding of the challenges associated with transferring reactions from the macro to the micro domain is required. This paper therefore aims to broach this problem by investigating the application of micro reactors to a range of commonly employed synthetic reactions including acylation, aldol, alkylation, 1,4-conjugate addition (Michael addition) and the Knoevenagel condensation. Comparison of the results obtained with traditional batch techniques enable us to highlight some of the advantages associated with micro reaction technology.
- Wiles, Charlotte,Watts, Paul,Haswell, Stephen J.,Pombo-Villar, Esteban
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p. 10757 - 10773
(2007/10/03)
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