Miki Koji, Ohe Kouichi, Uemura Sakae
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
J Org Chem. 2003 Oct 31;68(22):8505-13. doi: 10.1021/jo034841a.
Intermolecular cyclopropanation reactions of various alkenes with propargylic carboxylates 1 are catalyzed by [RuCl2(CO)3]2 to give vinylcyclopropanes 2 in good yields. The key intermediate of the reaction is a vinylcarbene complex generated in situ by nucleophilic attack of a carbonyl oxygen of the carboxylates to an internal carbon of the alkyne activated by the ruthenium complex. A variety of transition-metal compounds other than the Ru compound can also be employed in this system. Similar cyclopropanation proceeds with conjugated dienes as well to give trans-vic-divinylcyclopropane derivatives and cycloheptadiene derivatives 5, the latter being thermally derived from the initially formed cis-vic-isomers via Cope-type rearrangement. The present reaction is chemically equivalent to the transition metal-catalyzed cyclopropanation reaction using alpha-diazoketones as carbenoid precursors.
各种烯烃与炔丙基羧酸盐1的分子间环丙烷化反应由[RuCl2(CO)3]2催化，以良好的产率得到乙烯基环丙烷2。该反应的关键中间体是通过羧酸盐的羰基氧对由钌配合物活化的炔烃的内碳进行亲核攻击原位生成的乙烯基卡宾配合物。除了Ru化合物之外，该体系中还可以使用多种过渡金属化合物。共轭二烯也能发生类似的环丙烷化反应，生成反式-邻-二乙烯基环丙烷衍生物和环庚二烯衍生物5，后者是由最初形成的顺式-邻-异构体通过科普型重排热衍生而来。本反应在化学上等同于使用α-重氮酮作为类卡宾前体的过渡金属催化环丙烷化反应。
