Dirhodium(II) Complexes of 2-(Sulfonylimino)pyrrolidine: Synthesis and Application in Catalytic Benzylic Oxidation

A new class of dirhodium(II) tetraamidinates derived from 2-(sulfonylimino)pyrrolidines has been prepared through ligand substitution by using dirhodium(II) acetate, in which (3,1) geometric isomers are formed predominantly. Among these complexes, (3,1)-Rh2(Msip)4, exhibits good catalytic performance in benzylic oxidation. In the presence of (3,1)-Rh2(Msip)4 a variety of benzylic derivatives, including strongly electron-deficient arylalkanes such as 1-ethyl-4-nitrobenzene, are readily oxidized in water by the inexpensive oxidant T-HYDRO (R) (70 wt.-% aqueous tert-butyl hydroperoxide).