241 polarimeter

General Experimental Procedures Optical rotations were measured on a Perkin-Elmer 241 polarimeter (Waltham, MA, U.S.A.), and UV data were recorded on Beckman Coulter DU 800 spectrometer (Tokyo, Japan). IR data were recorded using a Shimadzu FTIR-8400S spectrophotometer (Tokyo, Japan). NMR experiments were performed on Bruker AV III 600 spectrometers operating at 600 MHz for 1 H and 150 MHz for 13 C, respectively. Chemical shifts are expressed in δ (ppm) referenced to solvent peaks at δ H 3.31 and δ C 49.2 for CD 3 OD, and coupling constants are in Hz. HR-ESI-MS spectra were obtained from a Thermo Scientific LTQ-Obitrap XL instrument (Thermo Scientific, Bremen, Germany). Silica gel (200-300 mesh, Qingdao Marine Chemistry Co., Ltd.) and Sephadex LH-20 (GE Healthcare, U.S.A.) were used for column chromatography. HPLC chromatography was performed on LC-6AD equipped with a UV detector of SPD-10A (Shimadzu, Kyoto, Japan), and a column of ZORAX SB-phenyl (250×10 mm, 5 µm, Agilent Technologies Co., Ltd., U.S.A.).