Selective introduction of a trifluoroacetyl group onto 4-vinylpyridines through magnesium-promoted reduction
                                
                                    
                                        作者:Hirofumi Maekawa、Yutaro Nishiyama                                    
                                    
                                        DOI:10.1016/j.tet.2015.07.046
                                    
                                    
                                        日期:2015.9
                                    
                                    Magnesium-promoted reductive coupling of 4-vinylpyridines and ethyl trifluoroacetate in the presence of chlorotrimethylsilane in N-methyl-2-pyrrolidone resulted in selective formation of the tri-fluoroacetylated compounds at the beta-olefinic carbon of the pyridine ring, the electron deficient carbon in good yields. In particular, 4-vinylpyridine with an aromatic ring at the beta-olefinic position of the pyridine ring gave higher yield of the trifluoroacetylated compound. The nitrogen atom of the pyridine ring may play an important role in the regioselectivity of the product. (C) 2015 Elsevier Ltd. All rights reserved.