| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
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.
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