An unexpected base-promoted isomerization of oxazolinylaryl oxiranes: synthesis of oxazolinylaryl alkanones

Aryl substituted oxazolinyloxiranes 1a–g have been found to undergo smooth isomerization into oxazolinyl substituted aryl alkanones 2a–g upon treatment with LDA in Et2O at −98°C, warming to room temperature and quenching with satd aq. NH4Cl. A mechanism involving an oxazoline-assisted ortho lithiation of the aryl group (cis to the oxazoline system) of oxiranes 1 is proposed.