(-)-Versicolamide B and (+)-Versicolamide B are spiro
indolealkaloids isolated from the fungus Aspergillus that belong to a class of naturally occurring
2,5-diketopiperazines.[1] The versicolamides are structurally complex spiro-cyclized versions of prenylated cyclo(L-Trp-L-Pro) derivatives which possess a unique spiro-fusion to a
pyrrolidine at the 3-position of the
oxindole core together with the bicyclo[2.2.2]diazaoctane ring system. While (-)-versicolamide B was isolated from the
marine fungusAspergillus sp.[2] the enantiomer (+)-versicolamide B was isolated from the terrestrial fungi Aspergillus versicolor NRRL.[3]
The total asymmetric syntheses of both enantiomers have been achieved and the implications of their
biosynthesis have been investigated.[4]
References
^Borthwick AD (May 2012). "2,5-Diketopiperazines: Synthesis, Reactions, Medicinal Chemistry, and Bioactive Natural Products". Chemical Reviews. 112 (7): 3641–3716.
doi:
10.1021/cr200398y.
PMID22575049.