Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy

• Huili Liu,
• Kuan Zheng,
• Xiang Lu,
• Xiaoxia Wang and
• Ran Hong

Beilstein J. Org. Chem. 2013, 9, 983–990, doi:10.3762/bjoc.9.113

• after hydrolysis. This strategy also differentiates terminally substituted alkenes and constitutes a potentially novel synthetic approach for the efficient synthesis toward velbanamine. Keywords: alkene; desymmetrization; dioxygenation; lactone; PIFA; velbanamine; Introduction Stictosidine-derived

• leukemia [12][13][14]. Fragmentation of 3 under acidic conditions delivers two structural units, desacetylvindoline and velbanamine (2) [15]. The reassembling of catharanthine (1) and vindoline (5) into the parent alkaloids 3 and 4 by using FeCl3-promoted oxidative coupling supports the biogenesis of

• heterodimeric indole alkaloids [11]. Interestingly, velbanamine (2) was later identified in leaves and twigs of Tabernaemontana eglandulosa in 1984 [16]. Therefore, the syntheses of velbanamine (2) and structurally closely related alkaloids may be important for the syntheses of their dimeric alkaloids. The