Total Synthesis of Dragocins A–C via Electrochemical Cyclization

The first total synthesis of dragocins A–C, remarkable natural products containing an unusual C-4’oxidized ribose architecture bridged by a polyhydroxylated pyrrolidine, is presented through a route featuring a number of uncommon maneuvers. Several generations towards the target molecules are presented including the spectacular failure of a key C–H oxidation on a late- stage intermediate. The final route features rapid, stereocontrolled access to a densely functionalized pyrrolidine and an unprecedented diastereoselective oxidative electrochemical cyclization to forge the hallmark 9-membered ring. Preliminary studies suggest this electrochemical oxidation protocol is generally useful.