Kan C, Long C M, Paul M, Ring C M, Tully S E, Rojas C M
Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, USA.
Org Lett. 2001 Feb 8;3(3):381-4. doi: 10.1021/ol0069002.
[figure: see text] Photolysis of an allal C-3 azidoformate provoked intramolecular nitrene insertion into the glycal C=C unit and allowed direct incorporation of alcohol nucleophiles as beta-disposed substituents at C-1. The 2-amido allopyranoside products were elaborated via N-acylation and selective oxazolidinone hydrolysis, providing N-Boc-protected 2-amino sugars and simplifying stereochemical assignments. Synthesis of the potentially labile allal azidoformate was achieved via reaction of the corresponding carbonyl imidazolide with trimethylsilyl azide, facilitated by dibutyltin oxide.
[图：见正文] 烯丙基 C-3 叠氮甲酸酯的光解引发分子内氮烯插入糖烯的 C=C 单元，并允许醇亲核试剂作为 C-1 位的 β-取代基直接引入。通过 N-酰化和选择性恶唑烷酮水解对 2-酰胺基吡喃糖苷产物进行了进一步修饰，得到了 N-Boc 保护的 2-氨基糖并简化了立体化学归属。通过相应的羰基咪唑化物与三甲基硅基叠氮化物反应，在二丁基氧化锡的促进下，实现了潜在不稳定的烯丙基叠氮甲酸酯的合成。
