Cyclodipeptide 2,5-diketopiperazines (DKP)a re privileged structuralu nits presenti nd rugs and natural alkaloids.T his work reports an ew method for the synthesis of biologically important DKP scaffoldsb ased on an intramolecular nucleophilic a-addition of generala midest owards 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 syntheseso f6 -methoxyspirotryprostatin B( the first total synthesis), spirotryprostatinA,a nd spirotryprostatin B.

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.

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