A concise protecting-group-free synthesis of cephalosporolides E and F

Abstract

A concise protecting-group-free synthesis of cephalosporolides E and F has been described. The key steps involve the one-pot conversion of L-mannonic-γ-lactone to γ-vinyl-β-hydroxy-γ-lactone, cross-metathesis and Wacker-type oxidative spiroketalization. The internal olefin served as a latent keto functionality with excellent delivery of a regioselective keto group for spiroketalization. The synthetic strategy is protecting-group-free and marks the shortest route so far to cephalosporolides E and F.