Norbornene as well as its 5,6-disubstituted derivatives and oxa-norbornene undergoes a novel cyclopropanation with propargyl alcohol in methanol containig cationic (η5-cyclopentadienyl)tris(acetonitrile)ruthenium complexes as catalysts to give exo-3-acetyltricyclooctane derivatives. Cyclopentadienylruthenium catalysts having an electron-withdrawing substituent on the Cp ligand exhibited the highest activity and the cyclopropanation proceeded even at −20 °C. On the basis of a deuterium labeling experiment, a reaction mechanism involving a ruthenacycle intermediate is proposed.
降冰片烯及其 5,6-二取代衍
生物和氧杂
降冰片烯在
甲醇中与
丙炔醇发生了一种新的
环丙烷化反应,该反应以阳离子 (η5-
环戊二烯基) 三(
乙腈)
钌络合物为催化剂,生成了外-3-乙酰基三
环辛烷衍
生物。在 Cp
配体上具有一个抽电子取代基的
环戊二烯基
钌催化剂表现出最高的活性,即使在 -20 °C 下也能进行
环丙烷化反应。在
氘标记实验的基础上,提出了涉及
钌环中间体的反应机理。