Hamigerans R and S: Nitrogenous Diterpenoids from the New Zealand Marine Sponge <i>Hamigera</i> tarangaensis
作者:Ethan F. Woolly、A. Jonathan Singh、Euan R. Russell、John H. Miller、Peter T. Northcote
DOI:10.1021/acs.jnatprod.7b00960
日期:2018.2.23
isolated from the New Zealand marine sponge Hamigera tarangaensis. Among the new additions are hamigeran R (1), considered to be the first benzonitrile-based marine natural product, and hamigeran S (2), the first dimeric structure in the series. The formation of 1 and 2 is thought to occur via the reaction of hamigeran G with a nitrogen source, where the nitrile carbon of 1 is derived from the terpenoid
hamigerans D, G, L, and N–Q has been accomplished. A convergent approach was used to build the basic tricarbocyclic ring system bearing a 5‐6‐6 structure. A sequence of oxidative cleavage, homologation, and ring regeneration provided access to the 5‐7‐6 skeleton of hamigeran G. Based on the biogenetic hypothesis, elegant and highly efficient biomimetic transformations of hamigeran G into hamigerans D, N–Q