Chiral Total Synthesis of Indole Alkaloids of the Aspidosperma and Hunteria Types

Article abstract of DOI:10.1021/jo00289a025

Expeditious enantioselective syntheses of (+)-quebrachamine (6), (-)-aspidospermidine (7), (+)-demethoxyaspidospermine (8), and (-)-eburnamonine (9) were accomplished starting from (S)-lactone 1.The syntheses also complete formal, total syntheses of 12 other indole alkaloids of the Aspidosperma and Hunteria types.The key step in the synthesis of (+)-quebrachamine (6) was the Pictet-Spengler condensation of chiral C9 unit 10, derived from 1, with tryptamine.Another C9 unit (15) was also prepared from 1 and utilized for the syntheses of three other alkaloids, 7, 8, and 9.