Regioselective addition of organozinc reagents to 5,6-dihydropyridinium ions and synthetic equivalents. Factors effecting 1,2-versus 1,4-selectivity
                                
                                    
                                        作者:Jean Luc Bettiol、Richard J. Sundberg                                    
                                    
                                        DOI:10.1021/jo00056a007
                                    
                                    
                                        日期:1993.2
                                    
                                    Organozinc reagents undergo nucleophilic addition to 5,6-dihydropyridinium ions with 1,2-versus 1,4-regioselectivity depending on the structure of the organic group and the presence of magnesium salts. Addition of organozinc reagents to 2-cyano-5,6-dihydropyridines, which are synthetic equivalents of 5,6-dihydropyridinium ions, gives exclusively 1,2-addition products.