A base-free copper-assisted synthesis of C 2 -symmetric spirotelluranes and biaryls based on divergent stoichiometry of Na 2 Te.

A one pot Cu(I)-assisted synthetic methodology has been developed for the preparation of biologically important C 2 -symmetric spirodiaza, benzyloxy and benzoxytelluranes from 2-bromo- N -aryl benzamides, benzyl alcohols, and benzoic acids by using the tellurium dianion (Te 2- ) under base-free conditions. Furthermore, C-C coupled biaryl 1,1'-diamides have been prepared by using an excess of Na 2 Te under the same reaction conditions. The synthesized spirodiazatelluranes served as a potent catalyst for the reduction of H 2 O 2 and nitro-Michael reactions.