Novel stereoselective synthesis of spiroketal structure using Pd(II)-catalyst

- We developed a stereoselective spiroketalization using Pd(II)-catalyst.
- The mechanism explains the stability of transition state.
- The reaction proceeds without activation of the allylic alcohol.

We report a highly stereoselective palladium(II)-catalyzed intramolecular cyclization of 1,11-dihydroxyundec-9-en-5-one derivatives via unstable hemiacetal intermediates, in which cyclization occurs without activation of the allylic alcohol to afford spiroketal structures.