One-Pot Synthesis of Multisubstituted Butyrolactonimidates: Total Synthesis of (-)-Nephrosteranic Acid

Multisubstituted chiral butyrolactonimidates have been synthesized via a one-pot, three-step cascade reaction in which (R)-N-tert-butanesulfinyl imidates and α,β-unsaturated diesters undergo highly stereoselective Michael addition, anion-oxidative hydroxylation, and cyclization. The synthesized butyrolactonimidates are versatile intermediates for preparation of substituted butyrolactones and furans. The usefulness of this cascade reaction is demonstrated through the concise total synthesis of natural product (−)-nephrosteranic acid.