Versicolamide B

Structures of (-) and (+) Versicolamide B

(-)-Versicolamide B and (+)-Versicolamide B are spiroindole alkaloids 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 fungus Aspergillus 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

1. 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. PMID 22575049.
2. Tsukamoto S, Kawabata T, Kato H, Greshock TJ, Hirota H, Ohta T, Williams RM (February 2009). "Isolation of Antipodal (−)-Versicolamide B and Notoamides L− N from a Marine-Derived Aspergillus sp". Organic letters 11 (6): 1297–1300. doi:10.1021/ol900071c. PMID 19281134.
3. Greshock TJ, Grubbs AW, Jiao P, Wicklow DT, Gloer JB, Williams RM (April 2008). "Isolation, Structure Elucidation, and Biomimetic Total Synthesis of Versicolamide B, and the Isolation of Antipodal (−)‐Stephacidin A and (+)‐Notoamide B from Aspergillus versicolor NRRL 35600". Angewandte Chemie International Edition 47 (19): 3573–3577. doi:10.1002/anie.200800106. PMID 18389509.
4. Miller KA, Tsukamoto S, Williams RM (April 2009). "Asymmetric total syntheses of (+)-and (−)-versicolamide B and biosynthetic implications". Nature chemistry 1 (1): 63–68. doi:10.1038/nchem.110. PMID 20300443.