An in situ generated catalytic system comprised of a Pd-PEPPSI [Pyridine enhanced pre-catalystpreparation, initiation, and stabilization] complex, (NHC)PdBr2(Pyridine), and PPh3 co-ligand demonstratedexcellent activity for the Sonogashira cross-coupling reactions between phenylacetylene with aryl halides inneat water under the aerobic condition in presence of CuI as co-catalyst. The catalytic system was not onlycompatible with electronically diverse aryl bromides/ iodides but also effective for relatively difficult substrateslike heteroaryl bromides. Notably, under similar experimental conditions, the mixed PEPPSI/PPh3system displayed superior activity over the free Pd-PEPPSI or Pd-phosphine system.
This article presents an in situ Pd-PEPPSI/PPh3 catalytic system for aqueous Sonogashira reaction in presence of CuI under aerobic condition which was found to be highly efficient for coupling of anyl/heteroaryl halides with phenylacetylene to form substituted alkynes. Interestingly, it displayed superior activity over simple Pd-PEPPSI or Pd-PPh3 catalysts
Volume 133, 2021
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