Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5218658 | Tetrahedron | 2013 | 5 Pages |
A convenient method for the enantioselective synthesis of βâ²-hydroxy-β-amino esters was developed through intensive investigations of the reaction conditions. Dichloromethane (DCM)/2,2,2-trifluoroethanol (TFE) and 1,2-dichloroethane (DCE)/TFE combinations were found to be the appropriate co-solvents for the reaction. In this mixed solvent system, [Ru(cymene)Cl2]2-Sunphos exhibited unusually higher activity and selectivity than the corresponding [Ru(cymene)I2]2-Sunphos. In situ generated catalyst could be used for this transformation. Asymmetric hydrogenation of a series of βâ²-keto-β-amino esters derivatives using Ru-Sunphos complexes via dynamic kinetic resolution led to the corresponding βâ²-hydroxy-β-amino esters with ee up to 99.6% and de up to 98.8% (S/C=1000).
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