Identification of Suitable Ligands for a Transition Metal-Catalyzed Reaction: Screening of a Modular Ligand Library in the Enantioselective Hydroboration of Styrene
general modular synthetic scheme, a variety of chiral bidentate P/P-, P/S-, P/N-, and P/Se-ligands is accessible in an efficient divergent manner starting from phenol or naphthol derived backbone systems. A library of 20 selected ligands was tested in the Rh-catalyzed asymmetric hydroboration of styrene to give 1-phenylethanol in up to 91% ee after oxidative work-up. It was demonstrated that small variations
modular approach to a new class of structurally diverse bidentate P/N, P/P, P/S, and P/Se chelate ligands has been developed. Starting from hydroquinone, various ligands were synthesized in a divergent manner via orthogonally bis-protected bromohydroquinones as the central building block. The first donorfunctionality (L1) is introduced to the aromatic (hydroquinone) ligand backbone either by Pd-catalyzed