Phase‐Separable Polyisobutylene Palladium‐PEPPSI Precatalysts: Synthesis and Application in Buchwald–Hartwig Amination
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This paper reports the efficient synthesis of the first class of polyisobutylene(PIB)-supported palladium-PEPPSI precatalyst (PEPPSI = pyridine-enhanced precatalyst preparation, stabilization, and initiation). The new complexes are employed in Buchwald-Hartwig amination of aryl chlorides and are found to be reasonably active in the titled cross-coupling reaction. The supported catalysts are tested in polar (1,4-dioxane and 1,2-dimethoxyethane) as well as in aliphatic reaction media (toluene and n-heptane) and display superior activity in the highly lipophilic solvent (n-heptane). The catalytic efficacy of PIB-Pd-PEPPSI precatalyst is measured to be comparable to its nonsupported analog. Pd-leaching is determined by inductively coupled plasma mass spectrometry (ICP-MS) after a simple liquid/liquid extraction and is found to be 2 ppb in the product phase, translating into a recovery of ≈99.8% of the palladium.
author list (cited authors)
Balogh, J., Hlil, A. R., El‐Zoghbi, I., Rafique, M. G., Chouikhi, D., Al‐Hashimi, M., & Bazzi, H. S.