Regio- and Chemoselective Kumada Tamao Corriu Reaction of Aryl Alkyl Ethers Catalyzed by Chromium Under Mild Conditions

Acting as an environmentally benign synthetic tool, the cross-coupling reactions with aryl ethers via CO bond activation have attracted broad interest. However, the functionalizations of CO bonds are mainly limited to nickel catalysis, and selectivity has long been a prominent challenge when several CO bonds are present in the one molecule. We report here the first chromium-catalyzed selective cross-coupling reactions of aryl ethers with Grignard reagents by the cleavage of CO(alkyl) bonds. Diverse transformations were achieved using simple, inexpensive chromium(II) precatalyst combining imino auxiliary at room temperature. It offers a new avenue for buildup functionalized aromatic aldehydes with high efficiency and selectivity.