Preparation of Multi-substituted Dienyltin Compounds Using Zirconacycles and It's Application

锆杂环的锆-碳键通过与卤化试剂如NCS、NBS或碘反应而断裂。其中一个锆碳键卤化后，我们预期与三烷基氯化锡反应可以得到二烯基锡化合物。不幸的是，这一反应没有进行，但我们发现，在CuCl的存在下，得到了所需的化合物。首先，用NCS氯化四乙基锆环戊二烯，然后向混合物中加入氯化三丁基锡。向该混合物中加入CuCl。以77%的产率获得所需的二烯基锡化合物。以类似的方法，以70%和75%的产率得到了4-溴-1-二烯基锡化合物。通常，第一次氯化或溴化在sp2碳上进行。然而，具有芳基取代基的sp2碳不与NCS或NBS反应。与碘反应得到二碘化化合物。锆-苯炔配合物则以67%的产率得到卤代二烯基锡衍生物，而四苯基锆环戊二烯配合物在不同的条件下选择性地得到了二烯基单锡化合物和1，4-二烯基二锡化合物，产率分别为55%和46%。以相同的方式，以46%的产率获得四乙基二烯基二锡化合物。在化学计量或催化量的氯化铜存在下，得到各种锡杂环戊二烯。

Zirconium-carbon bonds of zirconacycles are cleaved by the reaction with halogenation reagents such as NCS, NBS or iodine. After the halogenation of one of zirconium-carbon bond, we expected the reaction with trialkyltin chloride can afford dienyltin compounds. Unfortunately, this reactions did not proceed, but we found that in the presence of CuCl, the desired compounds were obtained. First, tetraethylzirconacyclopentadiene was chlorinated with NCS and then tributyltin chloride was added to the mixture. To this mixture was added CuCl. The desired dienyltin compound was obtained in 77% yield. In a similar way, 4-bromo-1-dienyltin compounds were obtained in 70% and 75% yield.Unsymmetrical zirconacyclopentadienes with alkyl or aryl substitutents can be selectively monohalogenated. Usually, the first chlorination or bromination proceeded at the sp2 carbon. However, the sp2 carbon having aryl substituents does not react with NCS or NBS. Reaction with iodine afforded diiodinated compounds. In contrast, zirconium-benzyne complex gave the halodienyltin derivative in 67% yield.When tetraphenylzirconaycclopentadiene was used, under different conditions, dienylmonotin compounds and 1,4-dienylditin compounds were selectively prepared in 55% and 46% yields, respectively. In a same way, tetraethyldienylditin compound was obtained in 46% yield. In the presence of a stoichiometric or catalytic amount of copper chloride, various kinds of stanacyclopentadienes were obtained.