Chiral vicinal diols as platforms for separable diastereomers in Johnson–Claisen rearrangement: a new short route to (−)-nor-canadensolide, (−)-canadensolide and (−)-sporothriolide

The chiral vicinal diols prepared by asymmetric dihydroxylation in high enantioselectivities provide an excellent platform for separable diastereomers in the Johnson–Claisen rearrangement. The separated syn-diastereomers were converted into the advanced γ-(lactone-lactol) intermediates (in six steps, 26–27% overall yields) for the synthesis of (−)-nor-canadensolide, (−)-canadensolide and (−)-sporothriolide.