Brønsted acids of anionic chiral Co(<scp>iii</scp>) complexes as catalysts for the stereoselective synthesis of cis-4-aminofuranobenzopyrans
作者:Hua-Jie Jiang、Kun Liu、Jing Wang、Na Li、Jie Yu
DOI:10.1039/c7ob02452e
日期:——
A highly enantioselective interrupted Povarov reaction of salicylaldimines and 2,3-dihydrofuran was developed, through the elegant Brønsted acid catalysis of anionic chiral Co(III) complexes. This reaction affords the cis-4-aminofuranobenzopyran derivatives with up to 95% yield, >20:1 dr and 96:4 er. Moreover, a one-pot three-component procedure of salicylaldehydes, anilines, and 2,3-dihydrofuran proves
Tritylium cation catalyzed interrupted Povarov reactions afforded cis-4-aminobenzodihydropyrans in excellent yields (90%) within 10 min by lowcatalystloading (1 mol %). Lewis acidic catalysis mechanism by carbocation was proposed and validated. Switching a one-pot batch version of the reaction into a two-stage convergent continuous flow procedures received 10-fold time reduction to 1 min with 88%