(2S)-2-Hydroxy-2-methyl-3-oxobutanoic Acid Phenylmethyl Ester is an intermediate in the synthesis of (S)-α-Acetolactic Acid (A163805), one of the enantiomers of acetolactate, which is the substrate of Acetolactate decarboxylase, which catalyzes the conversion of both enantiomers of acetolactate to the (R)-enantiomer of acetoin.