Brönsted acid ionic liquid-catalyzed direct benzylation, allylation and propargylation of 1,3-dicarbonyl compounds with alcohols as well as one-pot synthesis of 4H-chromenes
作者:Kazumasa Funabiki、Takuya Komeda、Yasuhiro Kubota、Masaki Matsui
DOI:10.1016/j.tet.2009.07.012
日期:2009.9
Recyclable ionic Brönsted acid was prepared in nearly quantitative yield by reacting 1-butylimidazole with an equimolar amount of 1,3-propanesultone, followed by treatment with an equimolar amount of trifluoromethanesulfonic acid. The ionic Brönsted acid-catalyzed direct benzylation, allylation and propargylation of 1,3-dicarbonyl compounds with various alcohols in ionic liquid [N-ethyl-N-methyl imidazolium
通过使1-丁基咪唑与等摩尔量的1,3-丙磺酸内酯反应,然后用等摩尔量的三氟甲磺酸处理,以接近定量的产率制备可回收的离子布朗斯台德酸。在离子液体[ N-乙基-N-甲基咪唑三氟甲磺酸盐(EMIOTf)]中,离子布伦斯台德酸催化1,3-二羰基化合物与各种醇的直接苄基化,烯丙基化和炔丙基化,在100°C下进行3小时,在不使用任何危险或挥发性溶剂且没有任何副产物(例如盐)的情况下,以良好的优良收率获得了相应的产品。此外,将1,3-二羰基化合物串联苄基化-环化-脱水,得到官能化的4 H在该催化反应中也获得了1-色烯。