Novel conversion of aldopyranosides into 5-thioaldopyranosides via acyclic monothioacetals with inversion and retention of configuration at C-5
作者:Hironobu Hashimoto、Masashi Kawanishi、Hideya Yuasa
DOI:10.1016/0008-6215(95)00386-x
日期:1996.2
A new strategy for synthesis of 5-thioaldopyranosides was developed. This included the ring opening of d-aldopyranosides with dimethylboron bromide and thioacetic acid, giving the acyclic monothioacetals, followed by the intramolecular cyclization between C-5 and 1-S. Cyclization with inversion of configuration at C-5 was achieved by simultaneous S -deacetylation and intramolecular nucleophilic substitution
摘要研究了5-硫代吡喃吡喃糖苷合成的新策略。这包括d-醛吡喃糖苷与二甲基溴化硼和硫代乙酸的开环,得到无环单硫缩醛,然后在C-5和1-S之间进行分子内环化。通过同时进行S-去乙酰化和5-甲磺酰化的单硫缩醛的分子内亲核取代,得到5-硫-1-醛吡喃糖苷,从而在C-5构型发生环化。用Mitsunobu试剂对5-羟基单硫缩醛进行环化,得到相同的5-硫代-1.-醛吡喃糖苷。通过C-5的两次转化可以合成5-硫代-d-吡喃葡萄糖苷。一硫代乙缩醛的糖基5糖衍生物在S-脱乙酰基作用下自发环化,得到5- C-羟基5-硫代d-葡萄糖吡喃糖苷,将其在C-5脱氧,得到5-硫代-d-吡喃葡萄糖苷,并从一硫缩醛中净保留C-5的构型。立体选择性还原糖基5-ulose,然后用Mitsunobu试剂进行分子内环化,也得到了5-硫代-d-吡喃葡萄糖苷。1个对映异构体的策略被应用于5-硫-1-基半乳糖的合成。还报道了5-硫代半乳糖对α-1-岩藻糖苷酶(K