Asymmetric cyclopropanation of chalcones using chiral phase-transfer catalysts

The first phase-transfer catalyzed cyclopropanation reaction of chalcones using bromomalonates as the nucleophiles in a Michael Initiated Ring Closing reaction (MIRC) was developed. Key to success was the use of a free OH-containing cinchona alkaloid ammonium salt catalyst and carefully optimized li...

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Detalles Bibliográficos
Autores principales: Herchl, Richard, Waser, Mario
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2013
Materias:
Article
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3878557/
https://www.ncbi.nlm.nih.gov/pubmed/24391288
http://dx.doi.org/10.1016/j.tetlet.2013.02.095
Descripción
Sumario:The first phase-transfer catalyzed cyclopropanation reaction of chalcones using bromomalonates as the nucleophiles in a Michael Initiated Ring Closing reaction (MIRC) was developed. Key to success was the use of a free OH-containing cinchona alkaloid ammonium salt catalyst and carefully optimized liquid/liquid reaction conditions. The reaction performed well for electron neutral and electron deficient chalcones giving the products in yields up to 98% and with enantiomeric ratios up to 91:9.

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