rac-(2aS,2a1 R,3aR,3a1 S,5aS,6aR)-2a-Allyl-2,4-dichloro-2a,2a1,3a1,5a,6,6a-hexahydro-3aH-3-oxadicyclopenta[cd,gh]pentalen-3a-ol

Annulation Tactics of cis-syn-cis Triquinanes by Allylsilanes: Application of Hosomi-Sakurai Reaction Conditions

A stereoselective [3+2] cycloaddition approach to functionalized pentaquinanes starting from cis-syn-cis triquinanes, derived from Cookson's diones, is reported. This transformation involves generation of six new stereocenters in a single step leading to cis-anti-cis-syn-cis-anti-cis polyquinane systems. Our method prevents transannular cyclizations which are prevalent in these moieties. The structure and stereochemistry of target molecules are well-characterized based on NMR data and X-ray diffraction studies.