D-alal是通过使用NaBH4CeCl3 x 7 H2O系统还原大体积的甲硅烷基保护的1,5-脱水己基-1-en-3-uloses选择性获得的。该合成的关键点是保护基团的性质。当使用大体积的甲硅烷基如叔丁基二苯基甲硅烷基作为底物时,以> 99%的选择性获得了受保护的D-alal。相反,当使用乙酰化的烯酮时,仅获得保护的D-葡萄糖。还发现添加CeCl3 x 7 H2O会影响选择性。
D-alal是通过使用NaBH4CeCl3 x 7 H2O系统还原大体积的甲硅烷基保护的1,5-脱水己基-1-en-3-uloses选择性获得的。该合成的关键点是保护基团的性质。当使用大体积的甲硅烷基如叔丁基二苯基甲硅烷基作为底物时,以> 99%的选择性获得了受保护的D-alal。相反,当使用乙酰化的烯酮时,仅获得保护的D-葡萄糖。还发现添加CeCl3 x 7 H2O会影响选择性。
Efficient Synthesis of Rare Sugar <scp>d</scp>-Allal via Reversal of Diastereoselection in the Reduction of Protected 1,5-Anhydrohex-1-en-3-uloses: Protecting Group Dependence of the Stereoselection
作者:Takashi Fujiwara、Masahiko Hayashi
DOI:10.1021/jo801596q
日期:2008.11.21
loses using the NaBH4CeCl3 x 7 H2O system. The crucial point of this synthesis is the nature of the protectinggroup. When bulky silyl group such as t-butyldiphenylsilyl was used as substrate, protected D-allal was obtained in >99% selectivity. In contrast, when acetylated enone was used, protected D-glucal was obtained exclusively. The addition of CeCl3 x 7 H2O was also found to influence selectivity
D-alal是通过使用NaBH4CeCl3 x 7 H2O系统还原大体积的甲硅烷基保护的1,5-脱水己基-1-en-3-uloses选择性获得的。该合成的关键点是保护基团的性质。当使用大体积的甲硅烷基如叔丁基二苯基甲硅烷基作为底物时,以> 99%的选择性获得了受保护的D-alal。相反,当使用乙酰化的烯酮时,仅获得保护的D-葡萄糖。还发现添加CeCl3 x 7 H2O会影响选择性。
Oxidative Heck Reaction of Glycals and Aryl Hydrazines: A Palladium-Catalyzed <i>C</i>-Glycosylation
作者:Yaguang Bai、Le Mai Hoang Kim、Hongze Liao、Xue-Wei Liu
DOI:10.1021/jo401032r
日期:2013.9.6
An efficient Heck-type C-glycosylation of glycals via the C-N bond cleavage of aryl hydrazines has been developed. The flexibility of the reaction was tested by the substrate scope, consisting of glycals from different carbohydrate origins as well as aryl hydrazines with various substituents. Pure alpha-C-glycosides were obtained when (3R)-glycals were employed, whereas alpha,beta mixtures were observed with (3S)-glycals.