Development of a manufacturing process for (S)-3-(aminomethyl)-5-methylhexanoic acid, an anticonvulsant, is described. Initial preparation employed as Evans chiral alkylation on (4R,5S)-4-methyl-3-(1-oxo-4-methylpentyl)-5-phenyl-2-oxazolidinone, using benzyl bromoacetate. Use of tert-Bu bromoacetate proved advantageous for large-scale preparation Route selection for a low-cost manufacturing process was based on "ideal process" cost projections. Four routes were evaluated in the laboratory Of the four, two were scaled up in the pilot plant, resulting in selection of a route based on synthesis of racemic 3-(aminomethyl)-5-methylhexanoic acid, followed by resolution with (S)-(+)-mandelic acid.