Total Synthesis of Dragocins A−C through Electrochemical Cyclization

Abstract

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.