A New Entry to Asymmetric Synthesis of 1-Substituted 1,2,3,4-Tetrahydro-β-carbolines Employing a Pyroglutamic Acid Derivative as a Chiral Auxiliary - Itoh, Takashi; Nagata, Kazuhiro; Yokoya, Masashi; Miyazaki, Michiko; Ikeda, Sachiko; Matsuya, Yuji; Enomoto, Yasuko; Ohsawa, Akio (Synlett, 2002)