Asymmetric total synthesis of (+)-cardiobutanolide via an iterative asymmetric dihydroxylation in PEG

The stereoselective total synthesis of (+)-cardiobutanolide, a polyhydroxylated natural product, is achieved in high yield through Lu and Guo diene synthesis, Sharpless asymmetric dihydroxylation, and one-pot deprotection–lactonization. The utility of a recyclable reagent system in PEG for asymmetric dihydroxylation is demonstrated.