Total synthesis of (-)-orthodiffenes A and C.

The efficient and concise synthesis of (-)-orthodiffenes A and C has been accomplished for the first time in eight steps from readily available chiral synthons, D-mannose and D-ethyl lactate. Our work confirmed the complete structure of orthodiffenes A and C, including their absolute stereochemistry. The key steps of our total synthesis involved cis-fused tetrahydrofuran cyclization, one-pot deprotection-lactonization, and intramolecular benzoyl migration according to a biosynthetic hypothesis of orthodiffenes.