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

锆环的锆碳键是通过与卤化试剂如NCS、NBS或碘的反应而断裂的。其中一个锆碳键卤化后，我们期望与三烷基氯化锡反应可以得到二乙烯基锡化合物。不幸的是，这个反应没有进行，但我们发现在CuCl存在的情况下，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，然后加入三丁基氯化锡。在此混合物中加入氯化铜。以77%的收率得到了理想的二乙烯基锡化合物。同样，4-溴-1-二乙烯基锡化合物的产率分别为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单卤化。通常，第一次氯化或溴化发生在sp2碳上。然而，具有芳基取代基的sp2碳不与NCS或NBS反应。与碘反应产生二碘化化合物。而锆-苯配合物的卤化二乙烯基锡衍生物的产率为67%。以四苯基锆环戊二烯为原料，在不同条件下，选择性地制备了二烯基单丁化合物和1,4-二烯基二丁化合物，收率分别为55%和46%。以同样的方法，以46%的收率得到了四乙基二烯二丁化合物。在一定化学计量量或催化量的氯化铜存在下，可以得到不同种类的斯坦环戊二烯。

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.