Total Synthesis and Structural Revision of Clavilactone D

A structural revision of clavilactone D, a potent inhibitor of protein tyrosine kinases, was achieved by total syntheses of two newly proposed structures. The syntheses relied on ring‐opening/ring‐closing metathesis, which transformed a cyclobutenecarboxylate into a γ‐butenolide. The syntheses confirmed that the correct structure of clavilactone D has an amino group at C‐3 instead of a hydroxy group at C‐2 in the originally proposed structure. Easy D: A structural revision of clavilactone D was achieved by total syntheses of two newly proposed structures. The syntheses relied on ring‐opening/ring‐closing metathesis, which transformed a cyclobutenecarboxylate into a γ‐butenolide. The correct structure of clavilactone D has an amino group at C‐3 instead of a hydroxy group at C‐2 in the originally proposed structure.