Synthesis and catalytic properties of N-functionalized carbene complexes of rhodium(I) and ruthenium(II)

Abstract

Imidazolidin-2-ylidene derivatives of rhodium(I) and ruthenium(II), having 2-methoxyethyl substituent on the N-atom, [Rh(L)Cl(PPh3)2], [Rh(L)Cl(COD)] or [Ru(L)Cl2(arene)] (L1 = CN(Me)CH2CH2NCH2CH2OMe and L2 = CN(CH2CH2OMe)CH2CH2NCH2CH2OMe) have been prepared by treatment of [RhCl(PPh3)3], [RhCl(COD)]2 or [RuCl2(arene)]2 with the N-functionalized electron-rich olefins L1 = L1 or L2 = L2. All of the new carbene rhodium(I) or ruthenium(II) complexes have proved to be effective catalysts for the cyclopropanation reactions of diazoalkane derivatives with styrene and the rhodium(I) precursors lead to the highest catalytic activity.