Breaking point: An effective reductive cleavage of inert aryl CO bonds with an inexpensive iron catalyst has been developed. During this process, the reduction of the arene rings was not observed. This catalytic system also enabled the selective cleavage of the β‐O‐4 linkage of lignin model compounds under an atmosphere of hydrogen, thus offering an opportunity for the depolymerization of lignin.

Sollbruchstelle: Die reduktive Spaltung inerter arylischer C‐O‐Bindungen mit einem günstigen Eisen‐Katalysator wurde entwickelt. Eine Reduktion des Arens wird bei dieser Reaktion nicht beobachtet. Das Katalysatorsystem konnte zudem für die selektive Spaltung der β‐O‐4‐Verknüpfung von Lignin‐Modellverbindungen unter einer Wasserstoffatmosphäre verwendet werden und bietet somit eine Möglichkeit zur Depolymerisation von Lignin.

A simple method was developed for selective para-cyanation of alkoxy-and benzyloxy-substituted benzenes with 0.5 equivalents of potassium ferricyanide, 0.8 equivalants of copper(II) nitrate and 0.5 equivalents of iodine in acetonitrile. Among various phenyl carbon-hydrogen bonds, those at the para-position with regard to the alkoxy or benzyloxy groups were selectively cyanated in 20% to 87% yields (23 examples). The present method uses com-mercially available reagents, and can be performed on a ten gram-scale. Interestingly, methoxybenzene was cyanated in 32% yield in the absence of potassium ferricyanide, which suggests that the nitrile group of a part of the product is possibly from the solvent acetonitrile.

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