Total synthesis of (-)-borrelidin

The total synthesis of borrelidin has been achieved. The best feature of our synthetic route is Sml(2)-mediated intramolecular Reformatsky-type reaction for macrocyclization after esterification between two segments. The two key segments were synthesized through chelation-controlled carbotitanation, chelation-controlled hydrogenation, stereoselective Reformatsky reaction, and MgBr2.Et2O-mediated chelation-controlled allylation.