Synthesis of Halogenated Anilines by Treatment of NN-Dialkylaniline N-Oxides with Thionyl Halides

摘要

The special reactivity of N,N-dialkylaniline N-oxides allows practical and convenient access to electron-rich aryl halides. A complementary pair of reaction protocols allow for the selective para-bromination or ortho-chlorination of N,N-dialkylanilines in up to 69% isolated yield. The generation of a diverse array of halogenated anilines is made possible by a temporary oxidation level increase of N,N-dialkylanilines to the corresponding N,N-dialkylaniline N-oxides and the excision of the resultant weak N–O bond via treatment with thionyl bromide or thionyl chloride at low temperature.