Fe(OTf)₃-Catalyzed Synthesis of Boronic Ester Containing N,O-Acetal Structure

Abstract

A convenient approach acess to boronic ester containing N,O-acetal structure has been established through the Fe(OTf)3-catalyzed addition of N,O-acetal with organic boric acid. A series of N-O-acetal boronic ester compounds have been successfully prepared in 58%～98% yields. Moreover, these compounds retain the property of boronic ester and can be used for coupling reaction. Keywords iminonium; N,O-acetal; boronic ester; addition reaction 硼酸酯作为偶联试剂 [1] 被广泛构建 C-C 键和 C-杂键, 尤其由于其具有耐空气氧化、制备方便及便于保 存等优点, 被广泛用于复杂天然产物的合成及药物合成 产业化中. 另外, 因为硼是一种具备特殊配位的杂原子, 近年来含有硼酸结构或硼酸酯结构的药物分子也被广 泛研究. 如蛋白酶体抑制剂硼替佐米 [2] 和蛋白激酶抑制 剂枸橼酸伊沙佐米 [3] 与其他药物联可用于治疗多发性骨 髓瘤. 硼酸酯具有硼酸和二醇间可逆键合的性质, 在生 物医学领域也有应用 [4] . 其可以作为共价交联剂(DABo) 用于 3D 打印 [5] . 1959 年, Lorand 等 [6] 开创性地描述了硼 酸和单糖的环酯能力, 现已被成功应用于糖尿病患者长 期血糖监测的 EverSenses 技术中(Scheme 1).