RESUMEN
The asymmetric total synthesis of vinorine, a polycyclic and cage-like alkaloid, has been realized in a flexible approach. Key features of the current synthesis include an aza-Achmatowicz rearrangement/Mannich-type cyclization to install the highly functional 9-azabicyclo-[3.3.1]nonane scaffold, a high yield Fischer indole annulation to synthesize the common intermediate for sarpagine-ajamaline type alkaloids, and an Ireland-Claisen rearrangement to construct the C15-C20 bond.
RESUMEN
Cyclodipeptide 2,5-diketopiperazines (DKP) are privileged structural units present in drugs and natural alkaloids. This work reports a new method for the synthesis of biologically important DKP scaffolds based on an intramolecular nucleophilic α-addition of general amides towards an alkynamide system. The utility of this umpolung cyclization mediated by trimethyl phosphine and l-glutamic acid is highlighted by its application to the concise total syntheses of 6-methoxyspirotryprostatinâ B (the first total synthesis), spirotryprostatinâ A, and spirotryprostatinâ B.