Study of Cationic Palladium Complex-Catalyzed Cyclization-Hydrosilylation of α,ω-Diynes

阳离子钯配合物催化α,ω-二炔环化-硅氢加成反应的研究

基本信息

批准号：
15550098
负责人：
YAMAMOTO Keiji
金额：
$ 2.05万
依托单位：
Tokyo University of Science, Yamaguchi
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

1)Taking advantage of the findings involving the palladium-catalyzed dimerization-hydrosilylalon of l-alkynes with trichlorosilane, we have developed a cationic palladium complex, which exhibits a specific catalytic activity for an intramolecular dimerization-hydrosilylation, i.e., cyclization-hydrosilylation of α,ω-alkadiynes. Thus, we have prepared 5, 6-membered (or even 7-membered) (Z)-1-(trichlosilyl)methylene-2-mthylenecycloalkanes starting from 1,6-heptadiyne derivatives and their homologs using typically trichlorosilane as an added.In order to elucidate a possible catalytic cycle of this unique reaction, the cyclization-hydrosilylation of unsymmetrical 1,6-octadiyne was carried out to give exclusively, (Z)-1(1'-trichlorosityl)ethylidene -2-methylenecyclopentane. The results well implicate that the hydropalladation takes place at a terminal alkyne site giving a vinylidene-palladium species, the latter, in turn, undergoing the carbopalladation with an internal alkyne site to cycli … More ze, followed by substitution with the hydrosilane to form the observed product and regenerate most probably a hydridopalladium as an acive catalyst. It is worthy of note that HSiMe_nCl_(3n) (n = 0 - 2) are equally applicable to this catalytic cylization-hydroilylation, while this is not the case for the dimerization-hydrosilylation of 1-alkynes mentioned above.2)Truly unexpected reaction product has been obtained when 9-oxa-1-dodecen-6,11-diyne was used as a substrate in the cationic palladium complex-catalyzed cyclization-hydrosilylation using trichlorosilane as an added. The major product (75%) identified was the one arising from the cyclization between an internal alkyne site and a terminal alkene, whereas the minor product (25%) was obtained from the ordinary intramolecular diyne cyclization. Furthermore, we have experienced that α,ω-alkenynes undergo the present cyclization-hydrosilylation generally much faster than the corresponding α,ω-alkadiynes.The results may suggest that, in the above mentioned catalytic cycle, the tale of carbopalladation at the alkene site must clearly be enhanced than that at the alkyne site. Thus, it is logically suggested to conduct any hydrosilylative cross-coupling of alkynes with alkenes. Less

1)利用钯催化L-炔烃与三氯硅烷的二聚-氢化硅烷化反应的研究成果，我们开发了一种阳离子钯配合物，该络合物对分子内二聚-氢化硅烷化反应（即α的环化-氢化硅烷化反应）表现出特定的催化活性。因此，我们制备了5、6元（甚至是）。 7 元）(Z)-1-(三氯甲硅烷基)亚甲基-2-亚甲基环烷烃，以 1,6-庚二炔衍生物及其同系物为原料，通常使用三氯硅烷作为添加物。为了阐明这种独特反应的可能催化循环，进行不对称1,6-辛二炔的环化-氢化硅烷化仅得到， (Z)-1(1'-三氯甲基)亚乙基-2-亚甲基环戊烷该结果很好地表明氢钯化发生在末端炔位点，产生亚乙烯基-钯物质，后者又经历了具有内部的碳钯化。炔烃位点到环化… 更多 ze，然后用氢硅烷取代以形成观察到的产物，并很可能再生氢化钯作为值得注意的是，HSiMe_nCl_(3n) (n = 0 - 2) 同样适用于这种催化环化-氢化硅烷化反应，而上述 1-炔烃的二聚-氢化硅烷化反应则不然。2)当 9-oxa-1-dodecen-6,11-diyne 在阳离子反应中用作底物时，获得了真正意想不到的反应产物使用三氯硅烷作为添加物的钯络合物催化环化-氢化硅烷化确定的主要产物（75%）是由内部炔烃位点和末端烯烃之间的环化产生的产物，而次要产物（25%）是从内部炔烃位点和末端烯烃之间的环化产生的。此外，我们发现α,ω-烯炔的环化-氢化硅烷化反应通常比相应的反应快得多。结果可能表明，在上述催化循环中，烯烃位点上的碳钯化反应必须明显比炔烃位点上的碳钯化反应增强，因此，逻辑上建议进行任何氢化硅烷化交叉反应。炔烃与烯烃的偶联较少。