Stereocontrolled routes to β,β′-disubstituted α-amino acids

Owing to their significant abundance in natural products, chiral β,β′-disubstituted α-amino acids remain an important synthetic objective. Emphasis has been focused in this critical review on the great diversity of enantio- and diastereoselective methodologies to reach these highly functionalized compounds. The oldest and cutting edge synthetic methods are described in parallel with the synthesis of many relevant biologically active targets (224 references).