Ruthenium-Catalyzed Cyclization of Epoxide with a Tethered Alkyne: Formation of Ketene Intermediates via Oxygen Transfer from Epoxides to Terminal Alkynes
作者:Reniguntala J. Madhushaw、Ming-Yuan Lin、Shariar Md. Abu Sohel、Rai-Shung Liu
DOI:10.1021/ja049943c
日期:2004.6.1
Treatment of (o-ethynyl)phenyl epoxides with TpRuPPh(3)(CH(3)CN)(2)PF(6) (10 mol %) in hot toluene (100 degrees C, 3-6 h) gave 2-naphthols or 1-alkylidene-2-indanones very selectively with isolated yields exceeding 72%, depending on the nature of the epoxide substituents. Surprisingly, the reaction intermediate proved to be a ruthenium-pi-ketene species that can be trapped efficiently by alcohol to
在热甲苯(100 摄氏度,3-6 小时)中用 TpRuPPh(3)(CH(3)CN)(2)PF(6) (10 mol %) 处理(邻乙炔基)苯基环氧化物得到 2-萘酚或 1-亚烷基-2-茚满酮的分离产率超过 72%,这取决于环氧化物取代基的性质。令人惊讶的是,反应中间体被证明是一种钌-π-乙烯酮物质,它可以被醇有效地捕获以产生酯化合物。这种现象表明在钌配合物的催化下,一种新的氧从环氧化物转移到其末端炔烃。在反应产物和氘标记实验的基础上提出了一个合理的机制。2-萘酚产物被认为源自(邻烯基)苯基乙烯酮中间体的 6-endo-dig 环化,而 1-亚烷基-2-indanones 来自 5-endo-dig 环化途径。