Stereoselective Synthesis of α- and β-<scp>l</scp>-<i>C</i>-Fucosyl Aldehydes and Their Utility in the Assembly of <i>C</i>-Fucosides of Biological Relevance
作者:Alessandro Dondoni、Nicola Catozzi、Alberto Marra
DOI:10.1021/jo049406a
日期:2004.7.1
C-fucosyl serines and C-fucosyl asparagines. As a final test of the synthetic utility of the title aldehydes, the β-anomer was employed as starting material in the stereoselective synthesis of both R- and S-epimer l-C-fucosyl phenylhydroxy acetates. One epimer was obtained by reaction of the sugar aldehyde with phenylmagnesium bromide, oxidation of the resulting alcohol to ketone, addition of 2-lithiothiazole
的有效合成ö经由噻唑除了三-benzylated标题糖醛衍生物ö苄基升-fuconolactone接着将得到的thiazolylketose和噻唑甲酰基到变换进行说明的高立体选择性的脱氧。维蒂希这些醛与半乳糖和D-吡喃葡萄糖6-膦和减少的烯化所得的烯烃,得到α-和β连接的(1→6) -升- Ç -fucosyl二糖,即,β-升- Ç -Fuc-(1 →6)-α- d -Gal,α-升- ç -Fuc-(1→6)-α- d -Gal,和α-升-C -Fuc-(1→6)-α- d- Glc。将上述C-岩藻糖基醛的α-端基异构体转化为C-岩藻糖基甲基三苯基碘化碘,用BuLi处理后,从中生成相应的C-岩藻糖基亚甲基phosphor烷。此正膦与加纳醛反应(Ñ -Boc d -serinal丙酮化合物)和它的一碳同系物更高,得到烯烃从得到恶唑烷环,其减少和揭晓了甘氨组Ç -fucosylα氨基酸,即α-升-连接ç