Asymmetric intramolecular Friedel–Crafts reaction catalyzed by a spiropyrrolidine organocatalyst: Enantioselective construction of indolizine and azepine frameworks
作者:Yi-Hang Zhang、Yong-Hai Yuan、Shu-Yu Zhang、Yong-Qiang Tu、Jin-Miao Tian
DOI:10.1016/j.tetlet.2018.09.061
日期:2018.11
The asymmetric intramolecular Friedel–Crafts type Michael reaction of α,β-unsaturated aldehyde with pyrrole, catalyzed by a spiropyrrolidine (SP)-type organocatalyst, has been accomplished, which allows the construction of a series of azepine and indolizine frameworks with high to excellent enantioselectivities (up to 98% ee). Moreover, the substrate scope could be extended to generate a quaternary
螺吡咯烷(SP)型有机催化剂催化的α,β-不饱和醛与吡咯的不对称分子内弗里德-克来福特米歇尔反应得以完成,从而可以构建一系列从高到优的氮杂环庚烷和吲哚嗪骨架对映选择性(高达98%ee)。此外,可以扩大底物的范围以在吲哚嗪框架中生成四元中心(ee高达96%)。