Visible-light-induced copper-catalyzed oxidative esterification of α-azidoketones with diazoacetates: access to α-acyloxyacetates.

A copper(II)-catalyzed 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-mediated synthesis of α-acyloxyacetates from α-azidoketones and diazoacetates under visible light at room temperature is described. This reaction involves an oxidative esterification process, leading to the formation of two new C-O bonds with the elimination of dinitrogen molecules in the overall process. 20 examples of α-acyloxyacetates were synthesized in high yields (70-86%) by coupling various α-azidoketones with diazoacetates. α-Azidoketones containing electron-donating groups (Me, MeO), electron-withdrawing groups (CN, NO 2 ), halogen atoms (Cl, Br), and other aryl groups are compatible with various substituted diazoacetates (ethyl, tertiary butyl, benzyl), resulting in the formation of α-acyloxyacetates.