First Total Synthesis and Structural Confirmation of Fluvirucinine A₂ via an Iterative Ring Expansion Strategy

The first asymmetric total synthesis of fluvirucinine A₂ has been accomplished. A key feature of the synthesis is an iterative lactam ring expansion to provide rapid access to the 14-membered lactam skeleton and three stereogenic centers. The excellent remote control of the three stereogenic centers relied on stereoselective amidoalkylation followed by an amide−enolate-induced aza-Claisen rearrangement. In addition, the structure of fluvirucinine A₂ has been completely elucidated by our total synthesis.