Stereoselective Synthesis of an Immunomodulator (+)-Conagenin Using Dirhodium(II)-Catalyzed C-H Amination and Chelation-Controlled Reductions as Key Steps - Yakura, Takayuki; Yoshimoto, Yuya; Ishida, Chisaki; Mabuchi, Shunsuke (Synlett, 2006)