The synthesis of the pharmaceutical (R)-tolterodine is reported using lithiation/borylation–protodeboronation of a homoallyl carbamate as the key step. This step was tested with two permutations: an electron-neutral aryl Li-carbamate reacting with an electron-rich boronic ester and an electron-rich aryl Li-carbamate reacting with an electron-neutral boronic ester. It was found that the latter arrangement was considerably better than the former. Further improvements were achieved using magnesium bromide in methanol leading to a process that gave high yield and high enantioselectivity in the lithiation/borylation reaction. The key step was used in an efficient synthesis of (R)-tolterodine in a total of eight steps in a 30% overall yield and 90% ee.
报道了使用锂化/硼化-脱硼酸作为关键步骤合成药用(R)-托特罗定的方法。此步骤经过两种排列方式的测试:一个电中性芳基Li-氨基甲酸酯与一个富电子硼酸酯反应,以及一个富电子芳基Li-氨基甲酸酯与一个电中性硼酸酯反应。发现后者的排列比前者要好得多。通过在甲醇中使用溴化镁,进一步改进了方法,导致在锂化/硼化反应中获得高产率和高对映选择性的过程。关键步骤在总共八个步骤中以30%的总产率和90%的对映选择性高效合成了(R)-托特罗定。