Calixarene-based chiral primary amine thiourea promoted highly enantioselective asymmetric Michael reactions of α,α-disubstituted aldehydes with maleimides
                                
                                    
                                        作者:Mustafa Durmaz、Abdulkadir Sirit                                    
                                    
                                        DOI:10.1016/j.tetasy.2013.09.010
                                    
                                    
                                        日期:2013.12
                                    
                                    Calix[4]arene based chiral bifunctional thiourea-primary amines have been shown to act as effective catalysts for the Michael addition of aldehydes to maleimides for the first time. The corresponding adducts were generally obtained preferentially in (R)- or (S)-forms with high yields (up to 99%) and with high to excellent enantioselectivities (up to 98% ee). (C) 2013 Elsevier Ltd. All rights reserved.