Highly anti-Selective Catalytic Aldol Reactions of Amides with Aldehydes

Abstract

Melting points were uncorrected and measured with Yanaco MICRO MELTING POINT BY-1. 1 H and 13 C NMR spectra were recorded on a JEOL ECX-600 spectrometer in CDCl 3 unless otherwise noted. Tetramethylsilane (TMS) served as internal standard (δ = 0) for 1 H NMR, and CDCl 3 was used as internal standard (δ = 77.0) for 13 C NMR. Trichlorofluoromethane (CFCl 3 ) was used as internal standard (δ = 0) for 19 F NMR. IR spectra were measured with JASCO FT/IR-610 spectrometers. High-performance liquid chromatography was carried out using following apparatuses; SHIMADZU LC-10AT (liquid chromatograph), SHIMADZU SPD-10A (UV detector), and SHIMADZU C-R6A (Chromatopac). High resolution mass spectrometry was carried out using JEOL JMS-700 and BRUCKER DALTONICS BioTOFII. Column chromatography was conducted on Silica gel 60 (Merck), and preparative thin-layer chromatography was carried out using Wakogel B-5F. Barium bis-tert-butoxide (Ba(O t Bu) 2 ) was purchased from Kojyundo Kagaku Co., Ltd. Aldehydes and phenol derivatives were purchased from Tokyo Kasei Kogyo Co., Ltd. and purified by distillation or recrystallization. Starting amides were synthesized according to literature's methods. 1 Molecular sieves (powder) was purchased from Aldrich Co., Ltd., and it was used after activation (200 o C, <1 mmHg, 16 h). THF was purchased from Wako Junyaku Kogyo Co., Ltd. as a dry solvent.