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.