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Please login to access the full content or check if you have access via Variation 1: Synthesis of Aromatic Aldehydes by Oxidative Hydroxymethylation with Formaldehyde and 2,3-Dichloro-5,6-dicyanobenzo-1,4-quinone

DOI: 10.1055/sos-SD-025-00443

Schall, A.; Reiser, O.Science of Synthesis, (200725645.

Instead of using formaldehyde as the oxidant, as described in Section for the oxidative hydroxymethylation of phenols, 2,3-dichloro-5,6-dicyanobenzo-1,4-quinone in the presence of a Brønsted acid such as sulfuric acid can also be successfully employed for this process.[‌139‌] With this method, activated arenes can be formylated to give aromatic aldehydes 45 in high yields (Scheme 25). Due to the acidic conditions, byproducts from condensation of the intermediate arylmethanols are formed in some cases; moreover, competitive parallel oxidation of methyl substituents, if present in the starting material, to aldehydes is sometimes observed.

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