Catalytic Asymmetric Synthesis of Morpholines. Using Mechanistic Insights To Realize the Enantioselective Synthesis of Piperazines
Ying Yin Lau, Huimin Zhai and Laurel L. Schafer*
*Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada, Email: schaferchem.ubc.ca
Y. Y. Lau, H. Zhai, L. L. Schafer, J. Org. Chem., 2016, 81, 8696-8709.
DOI: 10.1021/acs.joc.6b01884 (free Supporting Information)
A tandem sequential one-pot reaction employing both hydroamination and asymmetric transfer hydrogenation reactions enables an efficient and practical enantioselective synthesis of 3-substituted morpholines from aminoalkyne substrates. A wide range of functional groups is tolerated. Hydrogen-bonding interactions between the oxygen and the [(S,S)-Ts-DPEN] ligand of the Ru catalyst are crucial for obtaining high ee's.
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