Selective lithiation and crystal structures of G1-carbosilane dendrimers with dimethoxybenzene functionalities
作者:Sjoerd Harder、Reinout Meijboom、John R Moss
DOI:10.1016/j.jorganchem.2003.12.047
日期:2004.4
zipper-like network of intermolecular C–H⋯O bonds. Direct lithiation of these dendrimers with n-BuLi in Et2O yields complete and selective lithiation in the aryl ring between the methoxy substituents. However, dendrimer 2 is also partially lithiated in the benzylic group. For the solid state structure of such lithiated dendrimers, a diamond-type assembly is predicted.
描述了以下树枝状聚合物的合成途径:Si [CH 2 CH 2 Si(Me)2 CH 2 -3,5-(MeO)2 -C 6 H 3 ] 4(2)和Si [CH 2 CH 2 Si( Me)2 -2,4-(MeO)2 -C 6 H 3 ] 4(4)。这些树状聚合物的晶体结构已经通过单晶X射线衍射确定。一种树枝状聚合物(2)显示出晶体学S 4。对称性和分子内C–H⋯O键,而另一个(4)显示晶体学C 2对称性,并嵌入分子间C–H⋯O键的拉链状网络中。这些树状大分子在Et 2 O中用n -BuLi直接锂化会在甲氧基取代基之间的芳环上产生完全和选择性的锂化。但是,树枝状聚合物2在苄基中也被部分锂化。对于这种锂化树枝状聚合物的固态结构,可以预测为菱形组装。