The Absolute Configuration of Axinellamine A, a Pyrrole Alkaloid of the Marine Sponge Axinella sp., was Determined as R by Synthesizing Its (S)-Isomer

✍ Scribed by Masanori Seki; Kenji Mori

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 247 KB
• Volume: 2001
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/1099-0690(200102)2001:3<503::aid-ejoc503>3.0.co;2-6

✦ Synopsis

Scheme 2. Synthesis of the achiral building block 7; reagents: (a) ICH 2 CO 2 Et, FeSO 4 •7H 2 O, H 2 O 2 , DMSO (72%); (b) (Boc) 2 O, DMAP, MeCN (93%); (c) DIBAL, CH 2 Cl 2 ; (d) (EtO) 2 P(O)CH 2 -CO 2 Et, NaH, THF (63% based on 3); (e) MnO 2 , CHCl 3 Scheme 3. Synthesis of (S)-axinellamine A (1); reagents: (a) Ph 3 P, DIAD, THF (98%); (b) (NH 4 ) 6 Mo 24 O 7 •4H 2 O, H 2 O 2 , EtOH (99%); (c) LDA, THF, then 7 (58% based on 5); (d) NaOMe, MeOH/ THF (90%)

10. The anion generated from (S)-10 by treatment with lithium diisopropylamide (LDA) was allowed to react with aldehyde 7 to give, in 58% yield based on 5, the N-Bocprotected (S)-axinellamine A (11). This was shown to be a