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(ClO 4 ) 2 in the presence of K 3 PO 4 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 p K a (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.