Propargylamine synthesis via direct oxidative C[sbnd]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 CC coupling reaction via CH 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 CC coupling transformation could proceed readily, with 96% conversion being achieved after 180min at 120°C in the presence of 5mol% MOF-199 catalyst. The Cu-MOF catalyst could be recovered and reused several times for the direct oxidative CC 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 CC coupling reaction. To the best of our knowledge, this transformation using a heterogeneous catalyst was not previously mentioned in the literature.