Stewart Ian C, Douglas Christopher J, Grubbs Robert H
The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Org Lett. 2008 Feb 7;10(3):441-4. doi: 10.1021/ol702624n. Epub 2008 Jan 5.
Efficiency in olefin cross-metathesis reactions is affected upon reducing the steric bulk of N-heterocyclic carbene ligands of ruthenium-based catalysts. For the formation of disubstituted olefins containing one or more allylic substituents, the catalyst bearing N-tolyl groups is more efficient than the corresponding N-mesityl catalyst. In contrast, the formation of trisubstituted olefins is more efficient using the N-mesityl-containing catalyst. A hypothesis to explain this dichotomy is described.
在降低钌基催化剂的N-杂环卡宾配体的空间位阻时，烯烃交叉复分解反应的效率会受到影响。对于含有一个或多个烯丙基取代基的二取代烯烃的形成，带有N-甲苯基的催化剂比相应的N-均三甲苯基催化剂更有效。相比之下，使用含N-均三甲苯基的催化剂形成三取代烯烃的效率更高。本文描述了一个解释这种二分法的假设。
