A base-mediated silylation reaction leading to benzyl silanes has been developed. Under transition-metal and solvent free conditions, the silylation of a wide array of p-quinone methides is achieved using a Cs₂CO₃ catalyst in yields up to 96%. Carboxylation of the as-obtained organosilane with gaseous CO₂ provides a new synthetic protocol for the preparation of carboxylic acid.