Pullaiah Kattanguru

A protecting-group-free synthesis of Hagen's gland lactones.

A practical protecting group free synthesis of Hagens gland lactones 1 and 2 is accomplished in four steps and 25.6 and 37.4% overall yields, respectively. The strategy relies on a one-pot conversion of D-glucono-δ-lactone to β-hydroxy-γ-vinyl-γ-lactone, cross-metathesis, and iodocyclization-deiodinization as key steps.

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

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.

Stereoselective inversion of γ-vinyl-γ-butyrolactone under palladium catalysis: application to the synthesis of (+)-exo- and (+)-endo-brevicomins

An efficient γ-epimerization of γ-vinyl-γ-butyrolactone is studied under palladium catalysis. The building blocks derived there in are used in an efficient stereoselective synthesis of (+)-exo- and (+)-endo-brevicomins.