Catalyst-controlled formal [4 + 3] cycloaddition applied to the total synthesis of (+)-barekoxide and (-)-barekol.

@article{Lian2010CatalystcontrolledF,
  title={Catalyst-controlled formal [4 + 3] cycloaddition applied to the total synthesis of (+)-barekoxide and (-)-barekol.},
  author={Yajing Lian and Laura C Miller and Stephen Born and Richmond Sarpong and Huw M L Davies},
  journal={Journal of the American Chemical Society},
  year={2010},
  volume={132 35},
  pages={12422-5}
}
The tandem cyclopropanation/Cope rearrangement between bicyclic dienes and siloxyvinyldiazoacetate, catalyzed by the dirhodium catalyst Rh(2)(R-PTAD)(4), effectively accomplishes enantiodivergent [4 + 3] cycloadditions. The reaction proceeds by a cyclopropanation followed by a Cope rearrangement of the resulting divinylcyclopropane. This methodology was applied to the synthesis of (+)-barekoxide (1) and (-)-barekol (2).