A and B were isolated from the lipophilic extract of Lyngbya majuscula collected from the eastern Caribbean. Itralamide B (1) showed cytotoxic activity towards human embryonic kidney cells (HEK293, IC50 = 6 μM). Preliminary studies disapproved the proposed stereochemistry of itralamide. In this paper, we will provide a full account of the total synthesis of four stereoisomers of itralamide B and the
Synthesis of dysideaproline E using organocatalysis
作者:Ernest Owusu-Ansah、Amanda C. Durow、John R. Harding、Angela C. Jordan、Susan J. O'Connell、Christine L. Willis
DOI:10.1039/c0ob00617c
日期:——
(S)-4,4-Dichloro-3-methylbutanoic acid was prepared in 51% overall yield from commercially available starting materials using an organocatalytic transfer hydrogenation to 4,4-dichloro-3-methylbut-2-enal in the key step. The (S)-dichloro acid was used as an intermediate in the first total synthesis of dysideaproline E and a diastereomer confirming the structure of the natural product.
A stereocontrolled totalsynthesis of the cyclodepsipeptide, itralamide B, has been achieved. Both R - and S -stereoisomers of the side chain were attached to the macrocyclic ring, however, the synthesized structure appears to be different from that of the marine natural product.
环缩肽、itralamide B 的立体控制全合成已经实现。侧链的 R - 和 S - 立体异构体都连接到大环上,但是,合成的结构似乎与海洋天然产物的结构不同。