Lithium Aluminium Hydride and Metallic Iron: A Powerful Team in Alkene and Arene Hydrogenation Catalysis

Knüpfer C, Färber C, Langer J, Harder S (2023)

Publication Type: Journal article

Publication year: 2023

Journal

DOI: 10.1002/anie.202219016

Abstract

Alkenes that normally do not react with LiAlH4 (3-hexene, cyclohexene, 1-Me-cyclohexene), can be reduced to the corresponding alkanes by a mixture of LiAlH4 and Fe⁰ (the iron was activated by Metal-Vapour-Synthesis). This alkene-to-alkane conversion with a stoichiometric quantity of LiAlH4/Fe⁰ does not need quenching with water or acids, implying that both H's originate from LiAlH4. The LiAlH4/Fe⁰ combination is also a remarkably potent cooperative catalyst for hydrogenation of multi-substituted alkenes and benzene or toluene. An induction period of circa two hours and the minimally required temperature of 120 °C, suggests that the actual catalyst is a combination of Fe⁰ and the decomposition product of LiAlH4 (LiH and Al⁰). A thermally pre-activated LiAlH4/Fe⁰ catalyst did not need an induction time and is also active at room temperature and 1 bar H2. A combination of AliBu3 and Fe⁰ is an even more active hydrogenation catalyst. Without pre-activation, tetra-substituted alkenes like Me2C=CMe2 and toluene could be fully hydrogenated.

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How to cite

APA:

Knüpfer, C., Färber, C., Langer, J., & Harder, S. (2023). Lithium Aluminium Hydride and Metallic Iron: A Powerful Team in Alkene and Arene Hydrogenation Catalysis. Angewandte Chemie International Edition. https://doi.org/10.1002/anie.202219016

MLA:

Knüpfer, Christian, et al. "Lithium Aluminium Hydride and Metallic Iron: A Powerful Team in Alkene and Arene Hydrogenation Catalysis." Angewandte Chemie International Edition (2023).

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