In organic synthesis, the Casiraghi formylation is the formation of a salicylaldehyde from a phenol and paraformaldehyde. The reaction requires a strong Brønsted base and a weak Lewis acid, and gives a methanol coproduct:
Formally, it combines the Cannizzaro disproportionation with a directed Friedel-Crafts acylation.
In Casiraghi's original 1978 formulation, Grignard reagents served as both the hindered base and Lewis acid.
When using MgCl2 with a nitrogen base, such as triethylamine, the reaction is also known as Casnati-Skattebøl formylation
Applications include the synthesis of tocopherol derivatives.
References }