Unveiling the catalytic nature of palladium-N-heterocyclic carbene catalysts in the alpha-alkylation of ketones with primary alcohols

Ovezova M., Eroglu Z., Metin O., Cetinkaya B., GÜLCEMAL S.

DALTON TRANSACTIONS, cilt.50, ss.10896-10908, 2021 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 50
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1039/d1dt01704g
  • Dergi Adı: DALTON TRANSACTIONS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aquatic Science & Fisheries Abstracts (ASFA), Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, EMBASE, MEDLINE
  • Sayfa Sayıları: ss.10896-10908
  • Atatürk Üniversitesi Adresli: Evet

Özet

We report herein the synthesis of four new Pd-PEPPSI complexes with backbone-modified N-heterocyclic carbene (NHC) ligands and their application as catalysts in the alpha-alkylation of ketones with primary alcohols using a borrowing hydrogen process and tandem Suzuki-Miyaura coupling/alpha-alkylation reactions. Among the synthesized Pd-PEPPSI complexes, complex 2c having 4-methoxyphenyl groups at the 4,5-positions and 4-methoxybenzyl substituents on the N-atoms of imidazole exhibited the highest catalytic activity in the alpha-alkylation of ketones with primary alcohols (18 examples) with yields reaching up to 95%. Additionally, complex 2c was demonstrated to be an effective catalyst for the tandem Suzuki-Miyaura-coupling/alpha-alkylation of ketones to give biaryl ketones with high yields. The heterogeneous nature of the present catalytic system was verified by mercury poisoning and hot filtration experiments. Moreover, the formation of NHC-stabilized Pd(0) nanoparticles during the alpha-alkylation reactions was identified by advanced analytical techniques.