Asymmetric synthesis of tetrahydropyran[3,2-c]quinolinones via an organocatalyzed formal [3 + 3] annulation of quinolinones and MBH 2-naphthoates of nitroolefin
                                
                                    
                                        作者:Jian Li、Qi-Long Hu、Xue-Ping Chen、Ke-Qiang Hou、Albert S.C. Chan、Xiao-Feng Xiong                                    
                                    
                                        DOI:10.1016/j.cclet.2019.08.040
                                    
                                    
                                        日期:2020.3
                                    
                                    An efficient asymmetric and enantio-swithchable organocatalytic [3 + 3] annulation reaction using MBH-2-naphthoates of nitroalkenes and 4-hydroxyquinolin-2(1H)-ones has been developed. Densely substituted tetrahydropyrano[3,2-c]quinolinones scaffolds with two adjacent stereogenic centers are obtained with high yield (up to 95% yield) and good stereoselectivities (up to >20:1 dr and 96% ee) in an enantio-switchable manner. Furthermore, gram scale synthesis was achieved and the nitro group could easily transform into an amino group without any appreciable loss in the diastereo- and enantioselectivity. (C) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.