Selective Intermolecular Coupling of Alkynes with Nitriles and Ketones via β,β‘ Carbon−Carbon Bond Cleavage of Zirconacyclopentenes
作者:Tamotsu Takahashi、Chanjuan Xi、Zhenfeng Xi、Motohiro Kageyama、Reinald Fischer、Kiyohiko Nakajima、Ei-ichi Negishi
DOI:10.1021/jo980022s
日期:1998.10.1
Selective intermolecular coupling of alkynes with nitriles and ketones was performed by the reaction of a mixture of alkynes and Cp(2)ZrEt(2) with nitriles and ketones, respectively. Hydrolysis of the mixture gave alpha,beta-unsaturated ketones and allylic alcohols in good to excellent yields, respectively. These reactions proceeded via zirconacyclopentenes which were prepared by the reaction of alkynes
炔与腈和酮的选择性分子间偶联是通过炔和Cp(2)ZrEt(2)的混合物分别与腈和酮反应进行的。混合物的水解分别以良好或优异的产率得到α,β-不饱和酮和烯丙基醇。这些反应是通过锆炔环戊烯进行的,该催化剂是由炔烃与Cp(2)ZrEt(2)反应制备的。由二苯乙炔和Cp(2)ZrEt(2)制备的氧化锆环戊烯的结构通过X射线分析确定。清楚地表明,在氧化锆环戊烯的β-和β'-碳之间存在一个单键。氧化锆环戊烯与腈或酮的反应通过氧化锆环戊烯的β,β'碳-碳键裂解进行。以类似的方式