The synthesis of the all-important dipeptide-like side chain involves alkylation of the tert-butyl ester of -alanine (2) with ethyl 2-bromo-4-phenylbutanoate (1); the presominane of the desired isomer is attributable to asymmetric induction from the adjacent chiral center. Reaction of the product with hydrogen chloride then cleaves the tert-butyl group to give the half acid (3). Coupling of that acid to the secondary amine on tetrahydroisoquinoline (4) gives the corresponding amine. The tert-butyl ester in this product is again cleaved with hydrogen chloride to afford moexipril (5).