Synthesis of Functionalized Azacalix[1]­arene[3]­pyridine Macrocycles from Cu(II)-Mediated Direct Amination Reactions of Arene through High Valent Arylcopper(III) Intermediates

Mediated by Cu­(ClO4)2 in the presence of K3PO4 under mild conditions, azacalix[1]­arene[3]­pyridines underwent arene C–H bond amination with a number of sulfonamides, imides, and saccharin to afford the diverse C–N bond forming products. Based on different reactivity between arylcopper­(II) and arylcopper­(III) compounds toward nitrogen nucleophiles, the reaction proceeded most likely through arene C–H bond metalation via reactive arylcopper­(III) intermediates and their binding to nitrogen anions which were derived from deprotonation of acidic N–H bonds of nitrogen nucleophiles of pKa (DMSO) < 17.5 followed by reductive elimination. The study not only provides a convenient and straightforward access to functionalized heteracalixaromatics that are not readily obtained by other means but also enriches our understanding of high valent organocopper chemistry.