Processes are disclosed for synthesizing an α-amino acid or α-amino acid derivative, from a starting compound having a carbonyl functional group (C=O), with hydroxy-substituted carbon atoms at alpha (α) and beta (β) positions, relative to the carbonyl functional group. An α-, β-dihydroxy carboxylic acid or carboxylate is dehydrated to form a dicarbonyl intermediate by transformation of the α-hydroxy group to a second carbonyl group (adjacent a carbonyl group of the starting compound) and removal of the β-hydroxy group. This dicarbonyl intermediate is optionally cracked to form a second dicarbonyl intermediate having fewer carbon atoms but preserving the first and second carbonyl groups. Either or both of the dicarbonyl intermediate and the cracked dicarbonyl intermediate are then reductively aminated.