Dezember

Bild des Monats Dezember 2021

Selective Aerobic Hydroxylations: The Clip-and-Cleave Concept

Aliphatic or aromatic aldehydes and ketones can be easily transformed to chelate ligands by imine condensation with a diamine (Clip reaction). These ligands can form copper(I) complexes which react with dioxygen to form a bis(m-oxido) copper dioxygen intermediate (top left: Stopped-Flow UV-Vis spectrum of the intermediate at −80 °C) which then hydroxylates the aldehyde/ketone substrate selectively. The hydroxylation product can then easily be isolated by hydrolysis (Cleave reaction). A quite special reaction is the hydroxylation of adamantane-1-carbaldehyde in secondary position (top right: molecular structure of the hydrazone protected derivative), which is usually the unfavourable position in adamantane chemistry involving electrophilic or radical C-H bond activation, in comparison to the tertiary position. Aerobic oxygenation reactions are quite desirable, since dioxygen is the “greenest” oxidant, due to its high abundancy and formation of water and hydrogen peroxide as side products.

More details can be found here:

Chem. Eur. J. 2015, 21, 11735-11744 (DOI: 10.1002/chem.201501003)

Chem. Eur. J. 2018, 24, 15543-15549 (DOI: 10.1002/chem.201802607)

Eur. J. Inorg. Chem. 2021, 1961-1970 (DOI: 10.1002/ejic.202100185)

Dieses Bild wurde eingereicht von Alexander Petrillo, AG Prof. Dr. Siegfried Schindler.

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