Autopol 6

Opitical rotations were measured on an Autopol VI (Serial #91058) manufactured by Rudolph Research Analytical, Hackettstown, NJ, USA. UV spectra were recorded by a Shimadzu UV-2401PC spectrometer. CD spectra were recorded using a JASCO J-810 spectropolarimeter. NMR spectra were recorded on Bruker Avance III 600 spectrometers. Electrospray ionization (ESI)-high-resolution mass spectrometry (HRMS) were recorded on an Agilent G6230 TOF spectrometer. Single crystal X-ray crystallography was determined on SMART APEX II DUO X-ray single crystal diffractometer using Cu Kα radiation. Preparative HPLC was performed on a Waters 2489 series instrument with a UV/Visible detector, using a reversed-phase C18 column (Phenomenex, 250 mm × 21.2 mm, 5 μm). Chiral HPLC was carried out on an Agilent 1260 liquid chromatograph, utilizing chiral analytical columns [(R, R) WHELK-01 column, 4.6 mm × 250 mm, 10 μm, 100 A].

All manipulations were carried out under the argon atmosphere using standard Schlenk techniques. All glassware were oven or flame dried immediately prior to use. All solvents were purified and dried according to standard methods prior to use, unless stated otherwise. ¹H NMR spectra were obtained at 400 MHz or 600 MHz and recorded relative to the tetramethylsilane signal (0 ppm) or residual protio-solvent (7.26 ppm for CDCl₃, 1.94 ppm for CD₃CN). ¹³C NMR spectra were obtained at 100 MHz or 150 MHz, and chemical shifts were recorded relative to the solvent resonance (CDCl₃, 77.16 ppm, CD₃CN, 1.32 ppm). Data for NMR are recorded as follows: chemical shift (δ, ppm), multiplicity (s = singlet, d = doublet, t = triplet, m = multiplet or unresolved, br = broad singlet, coupling constant(s) in Hz, integration). Infrared spectra were recorded on Nicolet FT-IR spectrometers. The accurate masses were measured by ESI-TOF using QTOF Ultima, G2-xs TOF from Waters (Milford, MA, USA), and microflex LRF MALDI-TOF. Optical rotations αD were obtained with AUTOPOL VI from rudolph-research-analytical. HPLC using chiral stationary phase columns by comparing the samples with the appropriate racemic samples, column and elution details specified in each entry.

The optical rotations and CD spectra were measured on Autopol VI in MeOH (Rudolph Research Analytical, Hackettstown, NJ, USA) and Chirascan CD spectrophotometer in MeOH (Applied Photophysics, Leatherhead, UK), respectively. The IR spectra via KBr pellets and UV spectra were recorded on Nicolet iS10 spectrometer (Thermo Fisher Scientific, Madison, WI, USA) and Shimadzu UV2401PC (Shimadzu, Kyoto, Japan), respectively. NMR spectra (500 MHz for ¹H and 125 MHz for ¹³C) were recorded using Avance III 500 MHz equipment (Bruker, Bremerhaven, Germany). HRFABMS data and HRESIMS data were determined using Fast-atom-bombardment mass spectrometry DFS (Thermo Fisher Scientific, Madison, WI, USA) and Shimadzu LC/MS-IT-TOF mass instrument (Shimadzu, Kyoto, Japan), respectively. Column chromatography was conducted on silica gel (200–300 mesh, Qingdao Puke Abruption Materials Co., Ltd. Qingdao, China) and Sephadex LH-20 (Shanghai Yuanye Bio-Technology Co., Ltd. Shanghai, China). ODS column chromatography was performed using C18 silica gel (Fuji Silysia Chemical Ltd. Kasugai, Japan). TLC was carried out on precoated glass silica gel GF254 plates and compounds were visualized under UV light or via heating silica gel plates sprayed with 5% H₂SO₄/EtOH.

1D and 2D NMR spectra were recorded on a Bruker Ascend 500 NMR spectrometer with TMS as internal standard; ESIMS, MS², and MS³ were measured on the Agilent LC/MSD Trap XCT spectrometer and HRESIMS were performed on an Agilent 6520 Accurate-MS Q-TOF LC/MS system; Optical rotations were obtained with an Autopol VI (Rudolph Research Analytical, Hackettstown, NJ); CD spectra were recorded on a Chirascan spectrometer (Applied Photophysics, UK); IR spectrum was acquired with a Bruker Vector-22 spectrometer with KBr pellets; Colum chromatography was performed on silica gel (80–100 mesh, Huiyou Silica Gel Development Co., Ltd. Yantai, China); Reversed phase medium pressure liquid chromatography (RP-MPLC) was performed on a Buchi Sepacore system; TLC analysis was run on HSGF₂₅₄ silica gel plates (1–40 μm, Huiyou Silica Gel Development Co., Ltd. Yantai, China); Preparative TLC was conducted with pre-coated silica gel HSGF₂₅₄ plate (Huiyou Silica Gel Development Co., Ltd. Yantai, China).