Propargylamine synthesis via direct oxidative C-C coupling reaction between N,N-dimethylanilines and terminal alkynes under metal-organic framework catalysis

Abstract

MOF-199, a highly porous metal-organic framework based on copper ions, was used as a heterogeneous catalyst for the direct oxidative C-C coupling reaction via C-H functionalization between N,N-dimethylaniline and phenylacetylene to form N-methyl-N-(3-phenylprop-2-ynyl)benzenamine as the principal product. The copper-catalyzed direct C-C coupling transformation could proceed readily, with 96% conversion being achieved after 180 min at 120 ̊C in the presence of 5 mol% MOF-199 catalyst. The Cu-MOF catalyst could be recovered and reused several times for the direct oxidative C-C coupling reaction without a significant degradation in catalytic activity. The MOF-199 exhibited similar activity to other Cu-MOFs such as Cu₂(BDC)₂(BPY), Cu(BDC), and Cu₂(BDC)₂(DABCO), while Ni-MOF and Co-MOF were found to be catalytically inactive for the direct oxidative C-C coupling reaction. To the best of our knowledge, this transformation using a heterogeneous catalyst was not previously mentioned in the literature.