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Structural Revisions of a Class of Natural Products: Scaffolds of Aglycon Analogues of Fusicoccins and Cotylenins Isolated from Fungi
Author(s) -
Tang Ying,
Xue Yongbo,
Du Guang,
Wang Jianping,
Liu Junjun,
Sun Bin,
Li XiaoNian,
Yao Guangmin,
Luo Zengwei,
Zhang Yonghui
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201600313
Subject(s) - cyclooctane , undecane , tetradecane , chemistry , carbon skeleton , bicyclic molecule , stereochemistry , organic chemistry , catalysis
Abstract The reisolation and structural revision of brassicicene D is described, and inspired us to reassign the core skeletons of brassicicenes C–H, J and K, ranging from dicyclopenta[ a , d ]cyclooctane to tricyclo[9.2.1.0 3,7 ]tetradecane using quantum‐chemical predictions and experimental validation strategies. Three novel, highly modified fusicoccanes, brassicicenes L–N, were also isolated from the fungus Alternaria brassicicola , and their structures were unequivocally established by spectroscopic data, ECD calculations, and crystallography. The reassigned structures represent the first class of bridgehead double‐bond‐containing natural products with a bicyclo[6.2.1]undecane carbon skeleton. Furthermore, their stabilities were first predicted with olefin strain energy calculations. Collectively, these findings extend our view of the application of computational predictions and biosynthetic logic‐based structure elucidation to address problems related to the structure and stability of natural products.