金霉酸（aureolic acids）是一类结构相近具有抗肿瘤活性的化合物，其中mithramycin，chromomycin和olivomycins已经成药，用来治疗多种癌症。但是化学合成aureolic acids类天然产物一直非常具有挑战性，因为aureolic acids结构中包含多种2-脱氧糖苷键，以β糖苷键为主。由于缺失2位官能团，使2-脱氧糖糖苷化反应失去了邻基参与作用，导致糖苷化构型难以控制。目前构建β-2-脱氧糖苷键以间接合成，或保护基控制选择性合成为主。这些方法存在糖砌块合成繁琐，糖苷化中间步骤多，脱除保护基麻烦，极大降低了糖苷化效率。添加剂的出现打开了一扇新的大门。添加剂控制糖苷化反应，简化糖砌块合成步骤，选择性好，普适性强。本项目旨在发展新型添加剂实现选择性构建2-脱氧糖苷键，应用添加剂合成mithramycin或类似物，并测试生物活性。

Aureolic acids are very useful antitumor antibiotics which have similar structure. mithramycin, chromomycin and olivomycins are used as anticancer drug for several type cancer. Selective synthesis of aureolic acids is still a very challenge work as it contains lots of β-2-deoxy glycosides. However selective synthesis of 2-deoxy glycosides is always challenge because there is no neighboring group participation effect. For now, the method of synthesis of β-2-deoxy glycosides is indirect synthesis which is low efficient because it needs more steps in the synthesis of building blocks and glycosylation. In this regard, the introduction of nucleophilic additives to modulate the condensation reaction has been an important step forwards as this opens up a new way to match donor and acceptor reactivity. In this project, some new additives will be developed to steroselectively synthesize α/β-2-deoxy-glycosylation. Mithramycin will be assembled in the presence of additive.