The title compound 2 was synthesized. Asymmetric epoxidation of 9 followed by reductive cleavage of the epoxide 10 and acidification gave a symmetrical spiroketal (3), to which pyrrole and benzoxazole moieties were introduced in an efficient manner by the previously developed method. Since the synthetic material was less stable than natural calcimycin under basic conditions, cleavage of the methyl ester was achieved with LiI-pyridine.
合成了标题化合物 2。先将 9 进行不对称环氧化反应,然后将
环氧化物 10 还原裂解并酸化,得到对称的螺酮醛(3),再用之前开发的方法将
吡咯和
苯并恶唑有效地引入其中。由于合成材料在碱性条件下不如天然
降钙素稳定,因此采用 LiI
吡啶裂解甲酯。