Rhodium‐Catalyzed Dynamic Kinetic Asymmetric Allylation of Phenols and 2‐Hydroxypyridines |
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Authors: | Dr Changkun Li Prof Dr Bernhard Breit |
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Institution: | Institut für Organische Chemie, Albert-Ludwigs-Universit?t Freiburg, Freiburg im Breisgau, Germany |
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Abstract: | Inspired by the mechanistic studies of rhodium‐catalyzed atom‐economic addition of carboxylate acids to allenes, a rhodium‐catalyzed dynamic kinetic asymmetric allylation of different nucleophiles with racemic allylic carbonates has been developed. High regio‐ and enantioselectivities can be obtained under neutral conditions and, furthermore, the chemoselectivities can be controlled by different diphosphine ligands. (R,R)‐QuinoxP* leads to selective O‐allylation of phenols, whereas when embedding (S,S)‐DIOP as the ligand, 2‐naphthol is ortho‐C‐allylated for the first time in high enantioselectivity. To this end, hydroxypyridines can be N‐allylated by RhI/(S)‐DTBM‐Segphos via the same intermediate as in the previously reported atom‐economic addition to allenes. |
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Keywords: | allylic substitution dynamic kinetic asymmetric transformations enantioselectivity phenol rhodium |
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