RESUMO
The total syntheses of the Lythracea alkaloids (+)-vertine and (+)-lythrine are described. Enantioenriched pelletierine is used as a chiral building block and engaged into a two step pelletierine condensation leading to two quinolizidin-2-one diastereomers in a 8 : 1 ratio. The major product is used in the synthesis of (+)-vertine via aryl-aryl coupling and ring closing metathesis to provide a Z-alkene α to the lactone carbonyl function. The same procedure was used for (+)-lythrine after base induced epimerization of the main quinolizidin-2-one diastereomer. Alternative classical ring closure strategies like macrolactonisation or aryl-aryl coupling failed.
Assuntos
Alcaloides/síntese química , Alcaloides/química , Lythraceae/química , Modelos Moleculares , Estrutura Molecular , Piperidinas/síntese química , Piperidinas/químicaRESUMO
A concise total synthesis of the strained pentacyclic alkaloid (+/-)-Vertine has been achieved in eleven steps with the key steps being pelletierine condensation, Suzuki-Miyaura coupling, and ring-closing metathesis.
