Ohe Kouichi, Yokoi Tomomi, Miki Koji, Nishino Fumiaki, Uemura Sakae
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
J Am Chem Soc. 2002 Jan 30;124(4):526-7. doi: 10.1021/ja017037j.
The reaction of cis vicinal acetylethynylcyclopropanes 1 with a catalytic amount of M(CO)5(THF) (M = Cr or W) in the presence of Et3N at room temperature gave ortho-substituted phenols 7 in good yields as valence isomerized products. In the absence of Et3N the reactions did not work at all. The reaction of a cyclopropane having an ester or an amide instead of an acetyl moiety with M(CO)5(THF) did not take place, whereas an ethynylvinylcyclopropane gave a mixture of 1- and 2-substituted 1,3,5-cycloheptatrienes. These valence isomerization reactions are assumed to proceed via the formation of vinylidene-metal intermediates 2 from terminal alkynyl moieties followed by [3,3]sigmatropy of 2 to give seven-membered carbene complexes 3.
在室温下，顺式邻位乙炔基环丙烷1与催化量的M(CO)₅(THF)（M = Cr或W）在三乙胺存在下反应，以良好的产率得到邻位取代的酚7作为价键异构化产物。在没有三乙胺的情况下，反应根本无法进行。具有酯基或酰胺基而非乙酰基的环丙烷与M(CO)₅(THF)不发生反应，而乙炔基乙烯基环丙烷则生成1-和2-取代的1,3,5-环庚三烯的混合物。这些价键异构化反应被认为是通过末端炔基部分形成亚乙烯基金属中间体2，然后2进行[3,3] - 迁移重排生成七元卡宾配合物3来进行的。
