Cycloisomerization of Enynes Catalyzed by Iron(0)−Ate Complexes
作者:Alois Fürstner、Rubén Martin、Keisuke Majima
DOI:10.1021/ja0532739
日期:2005.9.1
half-sandwich iron(0) complex [CpFe(C2H4)2] [Li(tmeda)] (1a), which is readily available in multigram quantities from inexpensive starting materials (ferrocene, ethylene, Li sand), is shown to be an efficient catalyst for the Alder-ene reaction of various 1,6(7)-enynes. Thereby, the presence of the labile alkene ligands in the ferrate catalyst is essential since the analogous complex [CpFe(CO)2]Na is
Cyclobutenes by Platinum-Catalyzed Cycloisomerization Reactions of Enynes
作者:Alois Fürstner、Paul W. Davies、Tobias Gress
DOI:10.1021/ja050845g
日期:2005.6.1
considerable strain in the products as witnessed by the productive formation of tricyclic skeletons, such as 7 or 9. Moreover, these products provide evidence for the mechanistic scenario of platinum-catalyzedcycloisomerization reactions previously proposed, which are thought to proceed via organo-platinum species that mimic the reactivity of metal-complexed "nonclassical" carbocations.
在甲苯中催化量的 PtCl2 存在下,在其炔部分上带有(富电子)芳基取代基的 1,6-烯炔重排为环丁烯衍生物。当在 CO (1 atm) 气氛下进行时,反应显着加速,最有可能是通过临时配位到这种 pi 酸性配体来增加金属模板的亲电性。这种转变允许在产物中建立相当大的应变,如三环骨架的生产性形成所证明的那样,例如 7 或 9。此外,这些产品为先前提出的铂催化的环异构化反应的机制场景提供了证据,这被认为通过模拟金属络合的“非经典”碳正离子反应性的有机铂物种进行。