title: Copper-catalyzed aerobic oxidative coupling: From ketone and diamine to pyrazine.
abstract: Copper-catalyzed aerobic oxidative C-H/N-H coupling between simple ketones and diamines was developed toward the synthesis of a variety of pyrazines. Various substituted ketones were compatible for this transformation. Preliminary mechanistic investigations indicated that radical species were involved. X-ray absorption fine structure experiments elucidated that the Cu(II) species 5 coordinated by two N atoms at a distance of 2.04 Å and two O atoms at a shorter distance of 1.98 Å was a reactive one for this aerobic oxidative coupling reaction. Density functional theory calculations suggested that the intramolecular coupling of cationic radicals was favorable in this transformation.
authors.affiliation: College of Chemistry and Molecular Sciences, Institute for Advanced Studies, Wuhan University, Wuhan 430072, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wu
authors.affiliation: College of Chemistry and Molecular Sciences, Institute for Advanced Studies, Wuhan University, Wuhan 430072, China. ; Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Huang
authors.affiliation: School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China.
authors.forename: Xiaotian
authors.initials: X
authors.lastname: Qi
authors.affiliation: School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China.
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Chemistry and Molecular Sciences, Institute for Advanced Studies, Wuhan University, Wuhan 430072, China. ; Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Molecular Sciences, Institute for Advanced Studies, Wuhan University, Wuhan 430072, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.affiliation: College of Chemistry and Molecular Sciences, Institute for Advanced Studies, Wuhan University, Wuhan 430072, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yi
authors.affiliation: College of Chemistry and Molecular Sciences, Institute for Advanced Studies, Wuhan University, Wuhan 430072, China.
authors.forename: Lingkui
authors.initials: L
authors.lastname: Meng
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
authors.forename: Emilio E
authors.initials: EE
authors.lastname: Bunel
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Miller
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Chih-Wen
authors.initials: CW
authors.lastname: Pao
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Jyh-Fu
authors.initials: JF
authors.lastname: Lee
authors.affiliation: School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Lan
authors.affiliation: College of Chemistry and Molecular Sciences, Institute for Advanced Studies, Wuhan University, Wuhan 430072, China. ; Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA. ; National Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, China.
authors.forename: Aiwen
authors.initials: A
authors.lastname: Lei
keywords: Aerobic Oxidative Coupling; C-N Bond Formation; Copper-Catalyzed; DFT Calculations; EPR; XAFS