Isoxazole to oxazole: a mild and unexpected transformationElectronic supplementary information (ESI) available. CCDC 962972-962975. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4cc07999j

3-Aryltetrahydrobenzisoxazoles prepared en route to the coleophomone natural products and analogues, were found to undergo a remarkable base-mediated rearrangement to 2-aryltetrahydrobenzoxazoles. The scope of this unprecedented, facile transformation was probed: a range of analogues was produced, a mechanism proposed, and an application demonstrated by synthesis of a known herbicidal compound. 3-Aryltetrahydrobenzisoxazoles undergo a remarkable base-mediated rearrangement to 2-aryltetrahydrobenzoxazoles. The scope of this facile transformation was probed and a mechanism proposed.