Copper-based metal-organic frameworks as catalysts for the amination of aryl iodides

Abstract

Copper-based metal-organic frameworks (Cu-MOFs) were successfully used for the amination of aryl iodides for the first time. The conditions were selected using four different Cu-MOFs in a model reaction of n-octylamine with iodobenzene. Efficient reaction requires the use of O,O′-bidentate ligands (2-acetylcyclohexanone, 2-isobutyrylcyclo-hexanone, rac-1,1′-bi(2-naphthol), or rac-BINOL), and, in the best cases, the yields of N-octylaniline can exceed 80%. The nature of MOF does not produce a strong effect on the reaction outcome. The amination of iodobenzene derivatives containing electron-donating and electron-withdrawing substituents in the para- and meta-positions was investigated. The study also demonstrated the possibility of successful N-arylation of adamantane-containing amines with iodobenzene and its derivatives in the presence of MOFs and rac-BINOL or 2-isobutyrylcyclohexanone ligands. The yields of the products were found to depend on the steric hindrances at the nitrogen atom, with the best yields (87–88%) being obtained in the N,N′-diarylation of adamantanediamines. Using the reaction of n-octylamine with iodobenzene, the possibility of catalyst reuse for up to 10 cycles was demonstrated.