Total syntheses of the marine sponge pigments fascaplysin and homofascaplysin B and C
摘要:
The Fascaplysinopsis spp. marine sponge pigments fascaplysin (1), homofascaplysin B (4), and homofascaplysin C (5) have been synthesized by peracid oxidation, reaction with oxalyl chloride/methanol, or Vilsmeier formylation, respectively, of the keystone intermediate 12H-pyrido[1,2-a:3,4-b']diindole (7). The versatile 7 was prepared from indole (17) in six steps (78% yield), a sequence in which the key reaction is the trifluoroacetic acid-induced ring closure of diindole 15, followed by Pd/C-catalyzed dehydrogenation of the crude mixture of cyclized products 25, 26, to give 7 in 93% yield from 15.
Total synthesis of the marine sponge pigment fascaplysin
作者:Benjamin Pelcman、Gordon W Gribble
DOI:10.1016/s0040-4039(00)97367-2
日期:——
Fascaplysin (1), an antimicrobial and cytotoxic red pigmentfrom the marinespongeFascaplysinopsissp., has been synthesized in seven steps from indole (65% yield). The pivotal intermediate in the synthesis is diindole 3 which is induced to undergo acid-catalyzed cyclization and dehydrogenation to afford the desired pentacycle 2 in > 90% yield. Peracid oxidation of 2 yields fascaplysin.