The key intermediate 2b for 3,5-cyclovitamin D ring A synthon 13 was prepared in 80% yield as a diastereomeric mixture (70:30) via intramolecular cyclopropanation from iodonium ylide 10b.
3,5-环
维生素D环A合成子的关键
中间体2b是由
碘鎓内鎓盐10b通过分子内
环丙烷化以80%的产率制备成非对映异构体混合物(70:30)。