The copper complexes with bis(oxazoline) or azabis(oxazoline) ligands, once supported on laponite clay by electrostatic interactions, are able to catalyze the insertion of carbenoids in benzylic C-H bonds. In contrast with rhodium catalysts, they are more active with tertiary than with secondary bonds, through a similar mechanism as shown by Hammet correlation. Enantioselectivities are only moderate, with values up to 50% ee. The immobilized catalysts are partially recoverable and the best results are obtained in the case of reactions with high chemoselectivity. © 2013 Elsevier Ltd. All rights reserved.
Fraile, J. M., Mayoral, J. A., Muñoz, A., & Santafé-Valero, J. (2013). Carbenoid insertions into benzylic C-H bonds with heterogeneous copper catalysts. Tetrahedron, 69(35), 7360–7364. https://doi.org/10.1016/j.tet.2013.06.088