An alternative approach to synthesize pedamide, a key building block of pederin was described. Iodine-induced asymmetric heterocyclization was used as the key step to construct the skeleton, a tetrahydropyran ring with three chiral centers. Brown＇s asymmetric allylation and Lewis acid-mediated allylation were investigated to introduce chains and chiral alcohols. Sharpless dihydroxylation decorated the side chain. And high optically pure target was obtained by removing the epimers formed in these reactions on column chromatography.C2009 Ji Jun Xue. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.
De Gang Liu Ji Jun Xue Zhi Xiang Xie Li Ping Wei Hua Bing Zhang Ying Li
The asymmetric total synthesis of herbarumin Ⅲ 3, a naturally occurred phytotoxin, along with 8-epi-herbantmin Ⅲ 22, was succeeded in 12 steps from n-butyraldehyde based on Brown＇s asymmetric allylation, taking modified Julia olefination and Yamaguchi＇s macro-lactonization as key steps.
Xue Song Chen Shi Jun Da Li Hong Yang Bo Yan Xu Ztfi Xiang Xie Ying Li
Two novel steroid-linked nitrogen mustard conjugates la and lb were synthesized by using estrogenic acid 4 coupled with aniline mustard 8 and phenol mustard 13 in an esterification or amidation procedure. Preliminary cytotoxic screening on cancer cell lines in vitro showed that, the steroid-ester linked nitrogen mustard conjugate la exhibited obvious increasing of activities.
Hua Bing Zhang Ji Jun Xue Xiao Long Zhao De Gang Liu Ying Li
