作者:Daisuke Domon、Kenshu Fujiwara、Yuko Ohtaniuchi、Akihiro Takezawa、Sayaka Takeda、Hidekazu Kawasaki、Akio Murai、Hidethoshi Kawai、Takanori Suzuki
DOI:10.1016/j.tetlet.2005.09.163
日期:2005.11
The C42–C52 part of ciguatoxin CTX3C (1) was synthesized from tri-O-acetyl d-glucal. The synthetic segment had a tetrahydropyran ring corresponding to the ‘C49-reduced’ L-ring of 1, designed to avoid side reactions due to acid-labile C49 acetal carbon during acidic reductive conditions planned in further synthesis toward 1. The vicinal dimethyl part at C47–C48 was constructed by a stepwise conjugate
瓜瓜毒素CTX3C(1)的C42–C52部分是由三邻乙酰基d-葡糖醛合成的。合成链段具有对应于“ C49还原” L环的1的四氢吡喃环,旨在避免在计划进一步合成为1的酸性还原条件下,由于酸不稳定的C49乙缩醛碳引起的副反应。通过分步共轭加成/甲基化步骤构建C47-C48处的邻位二甲基部分。C50–C52单元的安装是通过Grignard添加C 3单元,然后进行螺环化和螺环缩醛的还原裂解。布朗的不对称巴豆基硼酸酯化实现了C42–C44部分的立体选择性组装。