已经研究了硝基阴离子在推拉异头糖烯烃上的亲核加成,结果表明,当应用于呋喃糖基亚基时,该反应为获得异头 γ-硝基酯开辟了一条新的有效途径。1,4-加成反应主要发生在不太拥挤的面,即与4,5-异亚丙基保护基团相反的一侧。观察到 E 和 Z 异构体的反应性非常不同,并且该实验结果在量子力学计算的基础上得到了合理化。对这些双 C,C-糖基化合物的硝基功能的化学操作产生了一系列新的 γ-糖基氨基酸,它们是手性结构单元,可用于合成糖肽寡聚物或用于构建生物活性化合物的支架。在相同的反应条件下,
Efficient methods for functionalization of readily available exo-glycals have been developed. Sequential palladium-catalysed cross-coupling of dibromo-substituted exo-glycals was first explored and allowed the formation of new disubstituted exo-glycals as single stereoisomers. Bromination of furano- and pyrano-methoxycarbonyl-exo-glycals led to a new series of monobrominated derivatives. These vinylic