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Updated: Aug 25, 2025
Preparation of N-2-alkoxyvinylsulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines
Published on: January 3, 2018
Rh-Catalyzed Sequential Asymmetric Hydrogenations of 3-Amino-4-Chromones Via an Unusual Dynamic Kinetic Resolution
Yunnan Xu1, Yicong Luo2, Jianxun Ye1
1Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Abstract:
Rh-catalyzed sequential asymmetric hydrogenations of 3-amino-4-chromones have been achieved for the first time via an unprecedented dynamic kinetic resolution under neutral conditions, providing (S,R)-3-amino-4-chromanols in high yields (up to 98%) with excellent enantio- and diastereoselectivities (up to 99.9% ee and 20:1 dr). The mechanistic studies based on control experiments and density functional theory (DFT) calculations suggest that the dynamic kinetic resolution process for the intermediate enantiomers generated in the first hydrogenation step proceeded via a stereomutation (or called chiral assimilation) pathway from an undesired enantiomer to the desired enantiomer rather than via traditional racemization of the undesired enantiomer. The protocol can be performed on a gram scale with a relatively low catalyst loading and offers a practical and convenient pathway for synthesizing a series of bioactive chromanols and their derivatives.
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