Functionalized Organocuprates: Structures of Lithium and Magnesium Grignard 2-Methoxyphenylcuprates

Lithium and magnesium Grignard diorganocuprates incorporating the functionalized aryl group 2-methoxyphenyl have been prepared and structurally characterized in the solid state. [Cu4Li2(C6H4OMe-2)6(THF)2] (2) and [Cu­(C6H4OCH3-2)2Mg­(THF)2X] (3-X; X = Cl, Br) all exhibit coordination of the s-block metal center by the methoxy oxygen, resulting in the formation of novel aggregates and favoring contact ion pair structures. In contrast, separate ion pair structures had previously been observed under similar conditions for nonfunctionalized arylcuprates. The magnesium organocuprates 3-Cl and 3-Br are of particular interest, being rare examples of structurally characterized Grignard-derived organocuprates and the first examples of functionalized Grignard organocuprates. All reported organocuprates undergo oxidative aryl coupling in the presence of O2 or PhNO2 to give 2,2′-dimethoxybiphenyl.