ROWA Lack GmbH, Siemensstr. 1-9, 25421 Pinneberg, Germany.
Org Biomol Chem. 2013 Aug 21;11(31):5109-16. doi: 10.1039/c3ob40554k. Epub 2013 Jun 28.
2,6-Bis(alkenyloxy) substituted arylboronic acids can be cyclotrimerized with the help of a hexaol as a template. First, the boronic acids are assembled by boronic ester formation with hexahydroxy-bicyclo[2.2.2]octane. Next, the resulting triboronates are cyclized by ring-closing metathesis to yield trimacrocycles as diastereomeric E/Z mixtures. Catalytic hydrogenation yields a single saturated trimacrocycle. Cleavage of the boronic ester functions liberates the template and generates a macrocycle with three boronic acid functionalities in endo-orientation. Due to this preorganization, macrocycles with boronic acids in endo-positions are good receptors for polyols. The binding of carbohydrates such as fructose was compared with the uptake of the respective templates into macrocycles with two or three boronic acids in endo-orientation.
2,6-双（烯丙氧基）取代的芳基硼酸在六醇的模板帮助下可以环三聚。首先，硼酸通过与六氢-双环[2.2.2]辛烷形成硼酸酯来组装。接下来，生成的三硼酸酯通过闭环复分解反应环化，生成作为非对映异构体 E/Z 混合物的三-大环。催化氢化生成单一的饱和三-大环。硼酸酯官能团的裂解释放出模板，并生成具有三个硼酸官能团在内向取向的大环。由于这种预组织，在内向位置具有硼酸官能团的大环是多元醇的良好受体。将果糖等碳水化合物的结合与相应的模板进入具有两个或三个硼酸在内向取向的大环的摄取进行了比较。
