Authors: Yajing Lian, Laura C. Miller, Stephen Born, Richmond Sarpong and Huw M. L. Davies
J. Am. Chem. Soc.,
2010, 132 (35), 12422–12425
The tandem cyclopropanation/Cope rearrangement between bicyclic dienes and siloxyvinyldiazoacetate, catalyzed by the dirhodium catalyst Rh2(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).