Metal-Free Synthesis of Unsymmetrical Ureas and Carbamates from CO<sub>2</sub> and Amines via Isocyanate Intermediates
作者:Yiming Ren、Sophie A. L. Rousseaux
DOI:10.1021/acs.joc.7b02905
日期:2018.1.19
A mild and metal-free synthesis of aryl isocyanates from arylamines under an atmosphere of CO2 was developed. The carbamic acid intermediate, derived from the arylamine starting material and CO2 in the presence of DBU, is dehydrated by activated sulfonium reagents to generate the corresponding isocyanate. The latter can be detected by in situ IR and trapped by various amines and alcohols to make unsymmetrical