Asymmetric Synthesis via Heterocyclic Intermediates; VII. Enantioselective Synthesis of (R)-α-Amino Acids using (S)-O,O-Dimethyl-α-methyldopa as Chiral Auxiliary Reagent - Schöllkopf, Ulrich; Hartwig, Wolfgang; Pospischil, Karl-Heinz; Kehne, Heinz (Synthesis, 1981)