An efficient enantioselective approach to multifunctionalized γ-butyrolactone: concise synthesis of (+)-nephrosteranic acid.

A short, efficient and novel approach for multifunctionalized γ-butyrolactone paraconic acids and its application to the total synthesis of (+)-nephrosteranic acid from readily available PMB ()-glycidyl ether as a starting material are described. Key transformations include asymmetric Michael addition catalyzed by chiral diphenylprolinol silyl ether and stereoselective α-methylation.