Modular Arene Difunctionalization of Unactivated C-O and C-H Bonds by Sequential Chromium-Catalyzed Transformations.

Sequential transformations of unactivated C-O and C-H bonds under chromium catalysis are described. The use of a N-benzyl-substituted imino group as an auxiliary combined with chromium(II) chloride as a precatalyst and 2,3-dichlorobutane as an oxidant allows the arene C-O and C-H bonds to sequentially couple to arylmagnesium reagents to incorporate two identical or different aryl groups into the ortho positions of benzaldehydes.