BINOL–quinine–squaramides as efficient organocatalysts for the asymmetric Michael addition of 2-hydroxy-1,4-naphthoquinone to nitroalkenes
                                
                                    
                                        作者:Enshan Zhou、Bin Liu、Chune Dong                                    
                                    
                                        DOI:10.1016/j.tetasy.2013.11.019
                                    
                                    
                                        日期:2014.1
                                    
                                    A set of BINOL-quinine-squaramides were synthesized, and then used as organocatalysts to promote the catalytic enantioselective Michael addition reaction of 2-hydroxy-1,4-naphthoquinone to nitroalkenes with excellent yields and ees (up to 99% yield and 93% ee) at low catalyst loading (0.5 mol %). (C) 2013 Elsevier Ltd. All rights reserved.