Anchimeric assistance by γ-substituents Z, Z=MeO, PhO, MeS or PhS, in reactions of the bromides (Me3Si)2(ZMe2Si)CSiMe2Br with AgBF4
作者:Colin Eaborn、Anna Kowalewska、J David Smith、Wlodziemierz A Stańczyk
DOI:10.1016/s0022-328x(01)01169-x
日期:2001.12
products by 19F-NMR spectroscopy, have led to the following approximate relative reactivities of the bromides and so to the relative abilities of the γ-Z groups to provide anchimeric assistance to the leaving of Br− in this reaction: Me, 1; Ph, 40; PhO, 3400; PhS, 5000; MeS, 7000; MeO, 54 000. In methanolysis in CH2Cl2, (Me3Si)2(MeOMe2Si)CSiMe2Cl has been found to be roughly 120 times as reactive as
制备了Z = PhO或MeS的新型有机硅溴化物(Me 3 Si)2(ZMe 2 Si)CSiMe 2 Br,并获得了先前报道的Z = H,F,Br,Me,Ph, MeO或PhS。通过19 F-NMR光谱法确定氟化物产物的比率,对成对的溴化物之间因Et 2 O中AgBF 4缺乏而产生的竞争导致了以下近似的溴化物相对反应性,因此也带来了相对能力该γ-Z组,以提供BR的邻位留下的援助-在这个反应中:我1;40岁;博士,3400; PhS,5000;MeS,7000;MeO,54000 。在CH 2 Cl 2的甲醇分解反应中,发现(Me 3 Si)2(MeOMe 2 Si)CSiMe 2 Cl的反应活性约为(Me 3 Si)2(PhOMe 2 Si)CSiMe的120倍。2 Cl。结果与先前可用信息的结合表明,在化合物(Me 3 Si)2(ZMe 2 Si)CSiMe 2 X:OCOMe中,Si-