Insertion reactions of organic anhydrides into the M–O bond of CuOtBu and Sb(OMe)3

The synthesis and structural characterization of the copper salts [Cu2(2-Boc-benzoate)4(dme)2] (1), [Cu(2-Boc-benzoate)2(tmeda)] (2), [Cu2(2-Boc-benzoate)2(dppm)] (3), [Cu(2-Boc-nicotinate)(PPh3)2] (4), [Cu2{2-Boc-5,6-anhydride-naphthylcarboxylate}2(dppm)2] (5) [dme = 1,2-dimethoxyethane, dppm = bis(diphenylphosphino)methane, tmeda = N,N′-tetramethylethylenediamine, Boc = tert-butoxycarbonyl] prove that cyclic organic anhydrides and dianhydrides readily insert into the Cu–O bond of [CuOtBu] forming carboxylate ligands with ester functionalities in the ligand periphery. [Sb(CO2Ph-o-CO2Me)2(OMe)(tmeda)] (6) was synthesised by insertion reaction of Sb(OMe)3 with phthalic anhydride.