Enantioselective total synthesis of borrelidin.

The first total synthesis of the natural product borrelidin is described. The propionate fragment of the molecule was concisely synthesized through catalytic enantioselective reductive aldol reactions, a catalytic Negishi coupling, and a catalytic directed hydrogenation. The propionate segment was then fused to the vinyl iodide fragment through a catalytic Sonogashira coupling. Subsequent catalytic hydrostannylation and catalytic cyanation allowed access to the target structure.