Título:
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Enantioselective protecting group-free synthesis of 1-S-ethyl-4-substituted quinolizidines
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Autor/a:
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Amat Tusón, Mercedes; Semak, Vladislav; Escolano Mirón, Carmen; Molins i Grau, Elies; Bosch Cartes, Joan
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Otros autores:
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Universitat de Barcelona |
Abstract:
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A practical enantioselective protecting group-free four-step route to the key quinolizidinone 6 from phenylglycinol-derived bicyclic lactam 1 is reported. The Grignard addition reaction to 6 takes place stereoselectively to give 1-ethyl-4-substituted quinolizidines 4-epi-207I and 7-9. Following a similar synthetic sequence, 9a-epi-6 is also accessed. However, the addition of Grignard reagents to 9a-epi-6 proceeds in a non-stereoselective manner. In order to gain insight into the different stereochemical outcome in the two series, theoretical calculations on the iminium salts A and B have been performed. The study concludes that the addition of the hydride, which is the step that determines the configuration of the final products, occurs in a stereoelectronic controlled manner. The theoretical study is in agreement with the experimental results. |
Materia(s):
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-Alcaloides -Síntesi asimètrica -Síntesi orgànica -Compostos bioactius -Alkaloids -Asymmetric synthesis -Organic synthesis -Bioactive compounds |
Derechos:
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(c) Amat Tusón, Mercedes et al., 2012
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Tipo de documento:
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Artículo Artículo - Versión aceptada |
Editor:
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Royal Society of Chemistry
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Compartir:
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