Stereoselective photochemical transformations of hexopyranosyl imides to highly functionalised heterocycles
作者:Swantje Thiering、Carsten E. Sowa、Joachim Thiem
DOI:10.1039/b010020j
日期:——
Reaction of O-protected glycosylamines with succinic anhydride and subsequent acylation afford both anomers of gluco- and manno-configurated N-glycosylsuccinimides. Irradiation with UV light of 254 nm wavelength leads to abstraction of H-2 and H-5, respectively, by the excited carbonyl function. The stereoselective recombination of the resulting 1,4- and 1,5-diradicals gives the annelated azacyclobutanol and azacyclopentanol derivatives, respectively. Owing to the strained four-membered rings, the azacyclobutanol derivatives fragment by an aza-analogous retroaldol addition to give the hexopyranosyl-annelated azepanedione systems.
O 型保护糖基胺与琥珀酸酐反应,随后进行酰化,可得到葡萄糖构型和甘露构型 N-糖基琥珀酰亚胺的两种异构体。用波长为 254 纳米的紫外线照射后,激发的羰基官能团分别萃取出 H-2 和 H-5。由此产生的 1,4- 和 1,5- 二环化合物通过立体选择性重组,分别得到环化的氮杂环丁醇和氮杂环戊醇衍生物。由于具有紧张的四元环,氮杂环丁醇衍生物通过氮杂环反醛醇加成法破碎,得到六吡喃糖基通道化氮杂环双酮系统。