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

通过与卤代试剂如NCS、NBS或碘的反应，切割锆环的锆碳键。其中一个锆碳键发生卤化反应后，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CuCl2存在下，得到了所需的化合物。首先用NCS对四乙基锆环戊二烯进行氯化，然后在混合物中加入三丁基氯化锡。在这种混合物中加入了氯化亚铜。以77%的产率得到了所需的二烯基锡化合物。以类似的方法合成了4-溴-1-二烯基锡化合物，产率分别为70%和75%。具有烷基或芳基取代基的不对称锆环戊二烯可以选择性地一卤化。通常，第一次氯化或溴化反应在sp2碳上进行。然而，具有芳基取代基的sp2碳不与NCS或NBS反应。与碘反应生成二碘化合物。以四苯基环戊二烯为原料，在不同条件下选择性地合成了二烯基二锡化合物和1，4-二烯基二锡化合物，产率分别为55%和46%。用同样的方法，以46%的产率得到了四乙基二烯基二锡化合物。在化学计量比或催化量的氯化铜存在下，得到了各种类型的双环戊二烯。

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.