Going to the source: Formamides or parentamines were used as an aminogroupsource for the silver‐mediated amination of benzoxazoles. Although reactions with formamides proceeded at high temperatures, the directamination with amines took place under much milder conditions (see scheme). Optically active aminogroups could also be installed without racemization.
An efficient copper-catalyzed electrophilic amination of benzoxazoles with O-benzoyl hydroxylamines is described, employing CuCl catalyst, PPh3 ligand, and (LiOBu)-Bu-t base. This simple air-stable copper catalysis enables the preparation of various 2-aminobenzoxazole derivatives at room temperature in good yields. (C) 2013 Elsevier Ltd. All rights reserved.