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Chiral Phosphoric Acid Catalyzed Kinetic Resolution of 2-Amido Benzyl Alcohols: Asymmetric Synthesis of 4H-3,1-Benzoxazines |
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| Authors: | Dr. Subramani Rajkumar Mengyao Tang Prof. Dr. Xiaoyu Yang |
| Affiliation: | 1. School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210 China These authors contributed equally to this work.;2. School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210 China University of Chinese Academy of Sciences, Beijing, 100049 China These authors contributed equally to this work.;3. School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210 China |
| Abstract: | An efficient method for the asymmetric synthesis of 4H-3,1-benzoxazines was developed by kinetic resolution of 2-amido benzyl alcohols using chiral phosphoric acid catalyzed intramolecular cyclizations. A broad range of benzyl alcohols (both secondary and tertiary alcohols) were kinetically resolved with high selectivities, with an s factor of up to 94. Mechanistic studies were performed to elucidate the mechanism of these reactions, wherein the amide moieties reacted as the electrophiles. Gram-scale reaction and facile transformations of the chiral products demonstrate the potential of this method in asymmetric synthesis of biologically active chiral heterocycles. |
| Keywords: | Alkohole Heterocyclen Kinetische Racematspaltung Organokatalyse Reaktionsmechanismen |