Solvent- and Catalyst-Free Direct Conversion of Malonic Esters to Carboxylic Acids via Thermal Cleavage of tert -Butyl Ester and Decarboxylation

A solvent- and catalyst-free method for the direct conversion of malonic esters to carboxylic acids has been developed via thermal cleavage of tert-butyl esters followed by decarboxylation. The protocol avoids hydrolysis and proceeds rapidly at 400 °C (2 min) under neat conditions, providing efficient access to carboxylic acids from relatively simple substrates. Although the elevated temperature may limit functional group compatibility, several groups are tolerated.