Lc 8a hplc

All reagents were used as received unless otherwise noted. Solvents were purified under nitrogen using a solvent purification system (Innovative Technology, Inc. Model # SPS-400–3 and PS-400–3. Enoates were distilled prior to use. Ni(COD)₂ (Strem Chemicals, Inc., used as received), 1,3-Bis(2,4,6-trimethyl-phenyl)-imidazolium chloride (IMes·HCl), and potassium tert-butoxide were stored and weighed in an inert atmosphere glovebox. Tri-N-butylphosphine was freshly distilled and used under an inert atmosphere. Aldehydes were freshly distilled using a Buchi GKR-51 Kuegelrhor. All reactions were conducted in flame-dried or oven-dried (120 °C) glassware under a nitrogen atmosphere. ¹H and ¹³C spectra were obtained in CDCl₃ at rt (25 °C), unless otherwise noted. Chemical shifts of ¹H NMR spectra were recorded in parts per million (ppm) on the δ scale from an internal standard of residual chloroform (7.26 ppm). Chemical shifts of ¹³C NMR spectra were recorded in ppm from the central peak of CDCl₃ (77.0 ppm) on the δ scale. HPLC purification was conducted using either a Shimadzu LC-8A HPLC with a Grace PN 81116 Alltima Silica 5 μm 250 mm × 10 mm prep column or a Waters Delta 600 Agilent Zorbax RX-SIL Prep HT 7 μm 21.2 mm × 250 mm column.