Palladium on carbon-catalyzed α-alkylation of ketones with alcohols as electrophiles: Scope and mechanism

Niklas R. Bennedsen, Rasmus L. Mortensen, Søren Kramer, Søren Kegnæs*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The α-alkylation of ketones with alcohols represents a green strategy for the formation of crucial carbon–carbon bonds since it only produces water as byproduct. In terms of reaction mechanism, the evidence for homogeneous catalysis supports a catalytic hydrogen-borrowing pathway; however, the reaction mechanism has not been investigated for heterogeneous Pd/C catalysts. Here, we report an improved method for α-alkylation of ketones with alcohols using commercially available Pd/C, ubiquitous in organic synthesis labs, as catalyst. The reaction conditions are mild compared to state-of-the-art for both homo- and heterogeneous catalysts, and the developed conditions produces quantitative yields for most ketones and alcohols. A hot filtration experiment and recycling of the catalyst supports the heterogeneous nature of catalysis. Importantly, the reaction mechanism is studied for the first time by a combination of stoichiometric experiments and kinetic analyses by in-situ IR (React-IR).
Original languageEnglish
JournalJournal of Catalysis
Volume371
Pages (from-to)153-160
Number of pages8
ISSN0021-9517
DOIs
Publication statusPublished - 2019

Keywords

  • Pd/C catalysis
  • Reaction mechanism
  • α-alkylation
  • Heterogeneous catalysis
  • In-situ IR
  • Kinetics
  • C-C bond formation

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