Patent ID: 7268253

Claim:
A process for preparing α,α-dialkyl-α-hydroxymethylcarboxylic acid derivatives or salts thereof of the formula (II) where R 1 and R 2 are each independently selected from the group consisting of linear and branched alkyl radicals and aralkyl radicals, R 3 is selected from the group consisting of hydrogen, optionally substituted linear and branched alkyl, aryl, aralkyl radicals, silyl radicals, alkali metal, alkaline earth metal, and amimonium, R 4 is hydrogen, a hydroxyl protecting group, alkali metal or alkaline earth metal, X is oxygen, where R 5 is selected from the group consisting of hydrogen, linear or branched alkyl, aryl, aralkyl radicals and silyl radicals, comprising: reacting α,α-dialkylcarboxylic acid derivatives or salts thereof of the formula (I) with paraformaldehyde in the presence of an amide base in a solvent or solvent mixture at a reaction temperature of from −40° C. up to the boiling point of the solvent or solvent mixture.