Short syntheses of the indole alkaloids alocasin A, scalaridine A, and hyrtinadine A-B
作者:Nurul H. Ansari、Björn C.G. Söderberg
DOI:10.1016/j.tet.2016.05.057
日期:2016.7
Expedient syntheses of the indole alkaloids alocasin A, scalaridine A, and hyrtinadine A-B are presented. All four natural products contain one or two 5-hydroxyindolyl units. Three palladium catalyzed reactions, an alkyne hydrostannylation, a Kosugi-Migita-Stille cross coupling and a reductive N-heterocyclization are the key steps in the syntheses.
Herein is reported a synthesis of alocasin A (1), an alkaloid component of Alocasia macrorrhiza, a herbaceous plant used in folk medicine throughout southern Asia. A double Suzuki-Miyaura cross-coupling reaction between a 3-borylindole and 2,5-dibromopyrazine was used to assemble the heteroaromatic framework of the natural product. Removal of the protecting groups gave a synthetic sample of 1, the spectroscopic data of which matched those in the isolation report of this compound.