Attack on fluorinated 2-aryloxazolines by organolithiums: dearomatisation, lithiation or substitution

Treatment of 4-, 3- or 2-aryl-4,5-diphenyloxazolines with isopropyllithium gives the products of dearomatising addition, fluorine-directed lithiation or nucleophilic aromatic substitution of fluoride depending on substitution pattern and conditions. In the case of the 4-fluoroaryl substrates, fluorinated 1,4-cyclohexadiene may be obtained in good yield.