We report here first examples of carbene-catalyzed allylation of benzaldehyde. N-Heterocyclic carbenes applied here, 9a and 10a, were derived from imidazolinium zwitterions, and contained sulfonate and sulfamate substituents, respectively. Different reaction conditions such as temperature, organic solvents, additive and bases were used to optimize the reaction. Sulfonate substituted NHC 9a is found more efficient organocatalyst for the allyltion of benzaldehyde (greater than 99 % yield at lower temperature) than sulfamate-based NHC 10a (a yield of no more than 15 %). These results are justified on the basis of philicity descriptors of the NHCs and their corresponding allyldichlorosilane complexes.
我们在此报告了卡宾催化
苯甲醛烯丙基化的第一个例子。这里应用的N-杂环卡宾9a和10a衍生自
咪唑啉鎓两性离子,并且分别含有
磺酸根和
氨基磺酸根取代基。使用不同的反应条件,如温度、有机溶剂、添加剂和碱来优化反应。发现
磺酸盐取代的 NHC 9a 比基于
氨基磺酸盐的 NHC 10a(产率不超过 15%)更有效地用于
苯甲醛的烯丙基化(在较低温度下产率大于 99%)。这些结果是基于 NHC 及其相应的烯丙基二
氯硅烷复合物的亲和性描述符来证明的。