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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)利用钯催化的l-炔与三氯硅烷的二聚-硅氢加成反应的研究结果，我们开发了一种阳离子钯配合物，它对分子内二聚-硅氢加成反应表现出特定的催化活性，即，α，ω-二炔的环化-氢化硅烷化。因此，我们制备了5、6元（或甚至7元）（Z）-1-以1，6-庚二炔衍生物及其同系物为原料，使用典型的三氯硅烷作为添加剂，制备（三氯甲硅烷基）亚甲基-2-亚甲基环烷烃。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，（Z）-1（1 '-三氯亚甲基）亚乙基-2-亚甲基环戊烷。结果表明，钯氢化反应发生在末端炔位，生成亚乙烯基钯物种，亚乙烯基钯物种又与内部炔位发生碳钯化反应，形成环钯化合物。 ...更多信息 ze，然后用氢硅烷取代以形成观察到的产物，并再生最有可能作为活性催化剂的氢化钯。值得注意的是，HSiMe_nCl_（3 n）（n = 0 - 2）同样适用于这种催化环化-氢化硅烷化，而对于上述1-炔的二聚-氢化硅烷化则不是这种情况。2）当9-氧杂-1-十二烯-6，以11-二炔为底物，三氯硅烷为添加剂，在阳离子钯络合物催化下进行环化-硅氢加成反应。确定的主要产品（75%）是一个内部的炔网站和末端烯烃之间的环化所产生的，而次要产品（25%）是从普通的分子内二炔环化。此外，我们还发现α，ω-烯炔的环化-硅氢加成反应一般比相应的α，ω-二炔快得多，这可能表明在上述催化循环中，烯烃位的碳钯化反应比炔位的碳钯化反应明显增强。因此，逻辑上建议进行炔与烯烃的任何氢化硅烷化交叉偶联。少