Competitive intramolecular TiC versus AlC alkene insertions: Examining the role of Lewis acid cocatalysts in Ziegler-Natta alkene insertion and chain transfer reactions
作者:Nancy S. Barta、Brian A. Kirk、John R. Stille
DOI:10.1016/0022-328x(94)05095-s
日期:1995.2
The reaction of (2-butyl-6-hepten-1-yl)titanocene chloride with (2-propyl-6-hepten-1-yl)aluminum dichloride:diethyl etherate produced 78% cyclization of the titanocene ligand, while less than 2% of the ligand originating on aluminum cyclized. In a complementary experiment, the reaction of (2-propyl-6-hepten-1-yl)titanocene chloride and (2-butyl-6-hepten-1-yl)aluminum dichloride:diethyl etherate again
对于模型Cp 2 Ti(Cl)R / RAlCl 2和Cp 2 Ti(Cl)R /的系统,已经研究了Ziegler-Natta烯烃插入的机理,包括催化剂/助催化剂的相互作用,链增长和链终止。MgX 2催化剂配合物。(2-丁基-6-庚-1-基)氯化钛新茂与(2-丙基-6-庚-1-基)氯化铝:二乙基醚的反应生成钛茂配体的78%环化,而小于2来自铝的配体的%环化。在一个补充实验中,(2-丙基-6-庚-1-基)二茂钛氯化物和(2-丁基-6-庚-1-基)二氯化铝:二乙基醚化物的反应仅再次产生了钛的分子内插入配体(58%)。基于这些结果,在这些反应条件下,没有发生通过钛和铝之间的过渡金属化的配体平衡,并且对于该过程证实了选择性插入到钛-碳键中。同样,用Cp 2 Ti(Cl)R / MgX 2进行配体环化也通过插入钛-碳键而发生。MgX 2生成的产品分布高度依赖溶剂。在CH 2 Cl 2中的环化非常有效