RT Journal Article SR Electronic T1 Copper-catalyzed aerobic oxidative coupling: From ketone and diamine to pyrazine JF Science Advances JO Sci Adv FD American Association for the Advancement of Science SP e1500656 DO 10.1126/sciadv.1500656 VO 1 IS 9 A1 Wu, Kun A1 Huang, Zhiliang A1 Qi, Xiaotian A1 Li, Yingzi A1 Zhang, Guanghui A1 Liu, Chao A1 Yi, Hong A1 Meng, Lingkui A1 Bunel, Emilio E. A1 Miller, Jeffrey T. A1 Pao, Chih-Wen A1 Lee, Jyh-Fu A1 Lan, Yu A1 Lei, Aiwen YR 2015 UL http://advances.sciencemag.org/content/1/9/e1500656.abstract AB 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.