Selective enhancement effects of silver salts on the transition metal-catalyzed synthesis of gem-difluorinated heterocyclics using 2,2-difluorohomopropargyl amides
作者:Satoru Arimitsu、Rebecca L. Bottom、Gerald B. Hammond
DOI:10.1016/j.jfluchem.2008.05.010
日期:2008.10
The addition of silver salts had an effect on the catalyst activity in the Pd(0)-catalyzed cyclization-coupling tandem reaction, as well as in the Rh(I)-catalyzed Pauson–Khand reaction. The cationic palladium complex generated from Pd(PPh3)4 (2.5 mol%) with AgSbF6 (1.5 equiv.) activates the triple bond of 2,2-difluoropropargylic amides to give the 4,5-disubstituted 3,3-difluoro-γ-lactams, through a
银盐的添加对Pd(0)催化的环化偶联串联反应以及Rh(I)催化的Pauson-Khand反应的催化剂活性产生影响。由Pd(PPh 3)4(2.5 mol%)与AgSbF 6(1.5当量)生成的阳离子钯络合物激活2,2-二氟丙炔酰胺的三键,得到4,5-二取代的3,3-二氟- γ-内酰胺,通过顺序的5 -endo-dig环化和交叉偶联反应。硅胶色谱后,将γ-内酰胺转化为开环的单氟乙烯基化合物。含催化量的[Rh(COD)2 ] 2的氟化1,7-烯炔酰胺的Pauson-Khand反应(5mol%)和AgOTf(20mol%)得到相应的宝石-二氟化双环内酰胺。