ausblenden:
Schlagwörter:
DIELS-ALDER REACTIONS; AMINO-ACID ESTERS; PICTET-SPENGLER REACTION; CHIRAL AUXILIARIES; AQUEOUS-SOLUTION; BENZYL ESTER; CYCLOADDITIONS
Zusammenfassung:
Schiff bases derived from tryptophan methyl ester and tryptamine react with Danishefkys diene in the presence of ZnCl2 to give enaminones which are subsequently transformed into indolo[2,3-a]quinolizidin-2-ones by acid-catalyzed cyclization. These tetracyclic aminoketones serve as viable intermediates in the construction of complex alkaloids, e. g. reserpine and deserpidine, and analogues thereof.