Hafnium Triflate as an Efficient Catalyst for Direct Friedel-Crafts Reactions of Chromene Hemiacetals
作者:Yan-Chao Wu、Hui-Jing Li、Li Liu、Nicolas Demoulin、Zhe Liu、Dong Wang、Yong-Jun Chen
DOI:10.1002/adsc.201000930
日期:2011.4.18
direct Friedel–Crafts reaction of chromene hemiacetals with indoles, furans and sterically hindered anilines has been accomplished with high selectivity and excellent yields in the presence of a catalytic amount of hafnium triflate [Hf(OTf)4, 0.1 mol%, 0–40 °C]. The mild conditions tolerate various sensitive functional and protecting groups, and the products were confirmed unambiguously from their spectra
与吲哚,色烯呋喃半缩醛和空间的直接的Friedel-Crafts反应受阻苯胺已经被以高选择性和高收率在三氟甲磺酸铪[HF(OTF)在催化量的存在下完成4,0.1摩尔%,0-40 °C]。温和的条件可以耐受各种敏感的官能团和保护基团,并且可以通过光谱和单晶X射线分析清楚地确认了这些产物。亚甲基半缩醛的直接Friedel-Crafts反应应启发并鼓励在开发温和的反应条件以有效地衍生含半缩醛化合物时考虑使用三氟甲磺酸ha。