Anchimeric assistance by the γ-N3 and γ-NCS groups in solvolysis of (Me3Si)2C(SiMe2 N3)(SiMe2Br) and (Me3Si)2C(SiMe2NCS)(SiMe2Br)
作者:Colin Eaborn、M.Novella Romanelli
DOI:10.1016/0022-328x(93)83006-h
日期:1993.6
The reaction of the bromide (Me3Si)2C(SiMe2N3)(SiMe2Br) (1) with MeOH gives the monomethoxy-compound (Me3Si)2C (SiMe2N3)(SiMe2OMe) in the presence of Et3N but, as a result of acid-catalysis of the departure of N3−, the dimethoxy- compound (Me3Si)2C(SiMe2OMe)2, in its absence. The reaction is much faster than that of (Me3Si)3CSiMe2Br, by a factor in the region of 105, revealing powerful anchimeric assistance
溴化物(Me 3 Si)2 C(SiMe 2 N 3)(SiMe 2 Br)(1)与MeOH的反应生成一甲氧基化合物(Me 3 Si)2 C(SiMe 2 N 3)(SiMe 2 OMe )中存在的Et 3 n,而是,作为N的离去酸催化的结果3 - ,所述化合物二甲氧基(ME 3 Si)的2 C(森达2 OME)2,在其不存在。该反应比(Me 3 Si)3 CSiMe的反应快得多2 BR,通过在10区域中的因子5,露出由γ-N强大邻位协助3组,以溴的离去- 。在这种解释相一致,反应不受甲醇钠加速,溶剂分解为CA。在CF 3 CH 2 OH中的速度是在MeOH中的150倍。相反,在与KSCN在MeCN,其中涉及的Br直接双分子置换反应-通过SCN - ,1是仅CA。反应活性是(Me 3 Si)3 CSiMe 2 Br的16倍。溴化物(Me 3 Si)2C(SiMe 2 NCS)(SiMe 2