作者:Helga Wiesenfeldt、Annette Reinmuth、Elke Barsties、Kaspar Evertz、Hans-Herbert Brintzinger
DOI:10.1016/0022-328x(89)85186-1
日期:1989.7
The formation of racemic and meso diastereomers of the disubstituted ansa-zirconocenes (CH3)2Si(1-C5H3-3-R)2ZrCl2 (R t-butyl, trimethylsilyl, α,α-dimethylbenzyl and 1-phenylcyclohexyl) from dimethylsilanediyl-bridged, symmetrically substituted bis-cyclopentadienyl dianion derivatives and ZrCl4·2THF has been studied under a variety of conditions. Rac/meso ratios close to 1 were obtained in all cases
的外消旋的形成和内消旋的非对映体取代柄-zirconocenes(CH 3)2的Si(1-C 5 H ^ 3 -3-R)2的ZrCl 2(R叔丁基,三甲基甲硅烷,α,α-二甲基苄基和1-已经在各种条件下研究了由二甲基硅烷二基桥连的对称取代的双环戊二烯基二价阴离子衍生物和ZrCl 4 ·2THF衍生的-苯基环己基)。在所有情况下,Rac /内消旋比均接近1。对于类似的钛和ha与R 3三甲基甲硅烷基的配合物,观察到相似的产物比率。rac / meso显着增加当在(CH 3)2 Si(1-C 5 H 2 -3-R-5-CH 3)2 ZrCl 2(RCH(CH 3)2,C(CH 3)3)。有人建议,用一个η中间体1结合的环配位体控制的立体化学过程袢茂金属形成。的晶体结构R,S - (CH 3)2的Si(1-C 5 H ^ 2 -3-C(CH 3)3 -5-CH 3)2 ZrCl 2被报道。