Efficient and recyclable Cu2(BPDC)2(DABCO)-catalyzed direct amination of activated sp3 C-H bonds by N-H heterocycles

A metal-organic framework Cu-2(BPDC)(2)(DABCO) was successfully synthesized and employed as an efficient heterogeneous catalyst for the direct C-N cross-coupling reaction via sp(3) C-N bond activation between N-H heterocycles and amides. Kinetic investigation was thoroughly conducted. The optimal conditions involve the use of Cu-2(BPDC)(2)(DABCO) catalyst (3%), di-tert-butyl peroxide oxidant (2 equivalents) in chlorobenzene solvent at 120 degrees C in 2 h. The Cu-2(BPDC)(2)(DABCO) offered higher catalytic activity than that of other Cu-MOFs such as Cu-2(BPDC)(2)(BPY), Cu-3(BTC)(2) and Cu-2(BDC)(2)(DABCO), and that of several common copper salts such as CuCl, CuBr, CuI, Cu(NO3)(2), and CuSO4. To investigate the mechanism, catalyst poisoning experiments and reactions with added radical scavengers were conducted. Furthermore, the catalyst could be recovered and reused several times without much decline in the reaction yield. (C) 2015 Elsevier B.V. All rights reserved.