To seek an approach toward the chemical conversion of C19-diterpenoid alkaloids to taxoids

This study, as a part of conversion of the C19-diterpenoid alkaloids to the taxoids, described the search of a suitable route to the key intermediate B with four approaches (ABC, ACB, BCA, and CAB) designed and examined. In these cases, a new and efficient approach (CAB) toward the synthesis of the vital intermediates or has been developed. The key steps include the use of a semipinacol rearrangement treatment of with NaOH/DMF under refluxing conditions for min to afford , and the rupture of the N-C-19 bond found in or to give or , respectively, through NBS imination followed by the creation of the oxaziridine or the nitrone and finally HIO4 oxidation cleavages.