Enantioselective Conjugate Addition of Catalytically Generated Zinc Homoenolate

Abstract

Material and MethodsGeneral. All reactions dealing with air-or moisture-sensitive compound were performed by standard Schlenk techniques in oven-dried reaction vessels under nitrogen atmosphere or in the argon-filled glove box. Analytical thin-layer chromatography (TLC) was performed on Merck 60 F254 silica gel plates. Flash chromatography was performed using 40-63 μm silica gel (Si 60, Merck). 1 H, 13 C and 19 F nuclear magnetic resonance (NMR) spectra were recorded on Bruker AV-400 (400 MHz) NMR spectrometers. 1 H and 13 C NMR spectra are reported in parts per million (ppm) downfield from an internal standard, tetramethylsilane (0.00 ppm) and CHCl3 (77.0 ppm), respectively. 19 F NMR spectra are referenced to external standard (CF3CO2H, -76.6 ppm). Gas chromatographic (GC) analysis was performed on a Shimadzu GC-2010 system equipped with an FID detector and a capillary column, DB-5 (Agilent J&W, 0.25 mm i.d. x 30 m, 0.25 μm film thickness). Chiral HPLC analysis was performed on a Shimadzu LC-20AD instrument using Daicel Chiralpak columns at room temperature (25-29 °C). Optical rotations were recorded on an Anton Paar MCP 150 machine. High-resolution mass spectra (HRMS) were obtained with a Q-Tof Premier LC HR mass spectrometer.