Organocatalytic Direct Asymmetric Aldol Reactions in Water

Abstract

General. Chemicals and solvents were purchased from commercial suppliers or purified by standard techniques. For thin-layer chromatography (TLC), silica gel plates (Merck 60 F 254 ) were used and compounds were visualized by irradiation with UV light and/or by treatment with a solution of phosphomolybdic acid in ethanol followed by heating. Flash column chromatography was performed using KANTO silica gel 60N (particle size 63-210 µ m). 1 H NMR and 13 C NMR spectra were recorded on JEOL JNM-AL spectrometer at ambient temperature. Chemical shifts are given in δ relative to tetramethylsilane (TMS), the coupling constants J are given in Hz. The spectra were recorded in CDCl 3 as solvent at ambient temperature, TMS served as internal standard (δ = 0 ppm) for 1 H NMR and CDCl 3 was used as internal standard (δ = 77.0) for