Stereospecific rearrangements of optically active 2-aryl-3-ethenyloxiranes to give optically active β-ethenylbenzeneethanols: Benzyl vs. allyl cations and an efficient synthesis of (s)-ibuprofen

Article abstract of DOI:10.1016/S0040-4039(97)00425-5

Rearrangements of aryl- and ethenyl-substituted oxiranes proceed well in the presence of triethylsilane and BF₃ to give optically active alcohols, which we have used for a synthesis of (S)-ibuprofen 1. We have also shown that a vinyl group migrates to a benzylic cation faster than a phenyl group migrates to an allyl cation.