Active Low-Valent Niobium Catalysts from NbCl<sub>5</sub> and Hydrosilanes for Selective Intermolecular Cycloadditions
                                
                                    
                                        作者:Yasushi Satoh、Yasushi Obora                                    
                                    
                                        DOI:10.1021/jo201757w
                                    
                                    
                                        日期:2011.10.21
                                    
                                    An active niobium catalyst was developed via a simple and nontoxic reduction method from NbCl5/hydrosilane and utilized for the selective [2 + 2 + 2] cycloaddition reaction of terminal alkynes and alkenes/alpha,omega-dienes, to give 1,3-cyclohexadiene derivatives in high yields with excellent chemo- and regioselectivity.