new, convenient, and selective 4-dimethylaminopyridine-catalyzed trifluoroacetylation of anilines with ethyl trifluoroacetate is described. Anilines, containing other functional groups, e.g. alcohols, phenols, hindered secondary amines, and secondary anilines, are also selectively trifluoroacetylated in high yields under these newly developed conditions.
Catalytic Ester−Amide Exchange Using Group (IV) Metal Alkoxide−Activator Complexes
作者:Chong Han、Jonathan P. Lee、Emil Lobkovsky、John A. Porco
DOI:10.1021/ja0527976
日期:2005.7.1
A process for preparation of amides from unactivated esters and amines has been developed using a catalytic system comprised of group (IV) metal alkoxides in conjunction with additives including 1-hydroxy-7-azabenzotriazole (HOAt). In general, ester-amide exchange proceeds using a variety of structurally diverse esters and amines without azeotropic reflux to remove the alcohol byproduct. Initial mechanistic studies on the Zr(Ot-Bu)(4)-HOAt system revealed that the active catalyst is a novel, dimeric zirconium complex as determined by X-ray crystallography.