3-[[[(1,1-Dimethylethoxy)carbonyl]amino]methyl]-5-methyl-hexanoic Acid Phenylmethyl Ester is an intermediate in synthesizing 4,9-Diisobutyl-1,6-diazecane-2,7-dione (D456300), an impurity of rac-Pregabalin (P704800) which is a GABA analogue used as an anticonvulsant.