Diastereoselective Intramolecular Ester Transfer Reaction of N-Alkenylcarbamate Derivatives Mediated by Zirconocene-Butene Complex: Preparation of α,γ-Disubstituted γ-Aminobutyric Acid (GABA) Derivatives and 2,4-Disubstituted Pyrrolidine Derivatives - Takigawa, Yasushi; Ito, Hisanaka; Omodera, Katsunori; Koura, Minoru; Kai, Yasuyuki; Yoshida, Emi; Taguchi, Takeo (Synthesis, 2005)