Conversional studies towards taxoids from C(19)-diterpenoid alkaloids by the BAC sequence

The conversional synthesis of taxoids by the BAC sequence from the C(19)-diterpenoid alkaloids, 14-acetyltalatisamine (1), yunaconitine (12), and 14-acetylchasmanine (19), was designed and explored. Two aconane-type diterpenes 17 and 28, the advanced intermediates for our conversional synthesis, were synthesized. The key steps include the rupture of the C(7)-C(17) bond, the formation of imine, and the denitrogenation.