Hand(ednes)s on an old ligand Hand(ednes)s on an old ligand.Two research groups report on different ways of modifying the Cp ligand so that Rh(III)-catalyzed C-H functionalization (A) would create preferred enantiomeric products (R and R′ are organic substituents; the star marks the product's chiral carbon). Hand(ednes)s on an old ligand.Two research groups report on different ways of modifying the Cp ligand so that Rh(III)-catalyzed C-H functionalization (A) would create preferred enantiomeric products (R and R′ are organic substituents; the star marks the product's chiral carbon). (B) Ye and Cramer chemically synthesized a chiral Cp ligand that determined the arrangement of substrate and reactant, resulting in high enantioselectivity (Me, methyl; Ph, phenyl; and tBu, tert-butyl). (C) Hyster et al. biochemically modified Cp to create an artificial metalloenzyme. An appropriately positioned glutamate side chain within the host protein accelerated the C-H activation step, and the asymmetric environment around the metal led to stereoselective coupling (Piv, pivaloyloxy). H Wang, F Glorius Science 2012;338:479-480 Published by AAAS

Fig. 1 Conceptual design of the chiral Cpx* complexes. B Ye, N Cramer Science 2012;338:504-506 Published by AAAS

Fig. 2 Structure of the chiral Cpx*Rh(I) complexes 1a to 1f. B Ye, N Cramer Science 2012;338:504-506 Published by AAAS

Fig. 3 Postulated model for the stereochemical preference with complex 1c. B Ye, N Cramer Science 2012;338:504-506 Published by AAAS