Solid-phase synthesis and configurational reassigment of callipeltin E.: Implications for the structures of callipeltins A and B
Solid-phase synthesis and configurational reassigment of callipeltin E.: Implications for the structures of callipeltins A and B
复制标题
DOI：
10.1021/jo060351h
复制
发表时间：
2006-08-18
影响因子：
3.6
通讯作者：
Lipton, Mark A.
中科院分区：
文献类型：
--
作者：
Calimsiz, Selcuk;Ramos, Angel I. Morales;Lipton, Mark A.
采用Fmoc固相合成法，经7步反应合成了天然产物callipeltin E（1，5）的两个可能的异构体，总收率分别为20%和26%。合成5的H-1 NMR谱与天然产物的H-1 NMR谱密切相关，而1的H-1 NMR谱则不相关，这证实了callipeltin E的N-末端残基的构型重新分配为D-别苏氨酸。这一结果强烈地暗示，在密切相关的环状缩肽callipeltin A和B中的相应残基也应该被认为是D-别苏氨酸残基。
Two possible isomers of the natural product callipeltin E (1, 5) were synthesized by using an Fmoc-based solid-phase strategy in 7 steps, in 20% and 26% overall yields, respectively. The H-1 NMR spectrum of synthetic 5 correlated closely with that of the natural product, whereas that of 1 did not, providing confirmation of the configurational reassignment of the N-terminal residue of callipeltin E as D-allothreonine. This result strongly implies that the corresponding residue in the closely related cyclic depsipeptides callipeltins A and B should also be considered a D-allothreonine residue.