Corrigendum: Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Amino Acid Derived Rhodium Complexes: On the Origin of Enantioselectivity and Enantioswitchability

Abstract

In the Full Paper by Adolfsson and co-workers, the structure of the valine-derived ligand 4 d is unfortunately incorrect. During further studies on amino acid derived hydroxamic acid ligands, the authors have found that the hydrogenation method used for generating compound 4 d, from its N-carbobenzyloxy (Cbz)-protected analogue, also cleaved the NO bond in the hydroxamic acid functionality. Therefore, the authors would like to withdraw all data concerning ligand 4 d, (i.e., the catalytic results presented in entries 7 and 8 in Table 2, and the preparation methods given in the Supporting Information). It should be added that other results and conclusions presented in the paper, are not affected by this error. To illustrate the latter, the rhodium-catalyzed transfer hydrogenation of acetophenone in 2-propanol using the L-phenylalanine-derived ligand 4 l, and conditions given in footnote [a] of Table 2, resulted in a 13 % conversion and 21 % enantiomeric excess (ee) (R) of 1-phenylethanol. When the same reaction was performed in the presence of LiCl (5 mol %), 64 % conversion and 34 % ee (R) of the secondary alcohol was obtained. The authors sincerely apologize for this error and any inconvenience it may have caused.1