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

Cite this

@article{b01d6c8a7d5c4be4b856dd5da323c531,
title = "Palladium on carbon-catalyzed α-alkylation of ketones with alcohols as electrophiles: Scope and mechanism",
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).",
keywords = "Pd/C catalysis, Reaction mechanism, α-alkylation, Heterogeneous catalysis, In-situ IR, Kinetics, C-C bond formation",
author = "Bennedsen, {Niklas R.} and Mortensen, {Rasmus L.} and S{\o}ren Kramer and S{\o}ren Kegn{\ae}s",
year = "2019",
doi = "10.1016/j.jcat.2019.01.034",
language = "English",
volume = "371",
pages = "153--160",
journal = "Journal of Catalysis",
issn = "0021-9517",
publisher = "Academic Press",

}

Palladium on carbon-catalyzed α-alkylation of ketones with alcohols as electrophiles: Scope and mechanism. / Bennedsen, Niklas R.; Mortensen, Rasmus L.; Kramer, Søren; Kegnæs, Søren.

In: Journal of Catalysis, Vol. 371, 2019, p. 153-160.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Palladium on carbon-catalyzed α-alkylation of ketones with alcohols as electrophiles: Scope and mechanism

AU - Bennedsen, Niklas R.

AU - Mortensen, Rasmus L.

AU - Kramer, Søren

AU - Kegnæs, Søren

PY - 2019

Y1 - 2019

N2 - 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).

AB - 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).

KW - Pd/C catalysis

KW - Reaction mechanism

KW - α-alkylation

KW - Heterogeneous catalysis

KW - In-situ IR

KW - Kinetics

KW - C-C bond formation

U2 - 10.1016/j.jcat.2019.01.034

DO - 10.1016/j.jcat.2019.01.034

M3 - Journal article

VL - 371

SP - 153

EP - 160

JO - Journal of Catalysis

JF - Journal of Catalysis

SN - 0021-9517

ER -