A Versatile Synthesis of Vinyl-Substituted Heterocycles via Regio- and Enantioselective Pd-Catalyzed Tandem Allylic Substitution
Chao Qian and Wenjun Tang*
*Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Ling Ling Road, Shanghai 200032, China, Email: tangwenjunsioc.ac.cn
C. Qian, W. Tang, Org. Lett., 2020, 22, 4467-4470.
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The use of the chiral bisphosphorus ligand WingPhos enables a versatile, regio- and enantioselective palladium-catalyzed tandem allylic substitution to provide a series of chiral vinyl-substituted heterocycles, including tetrahydroquinoxalines, piperazines, dihydro-2H-benzo[b][1,4]-oxazines, and morpholines, in exellent ees and yields. The protocol features mild reaction conditions.
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proposed mechanism for the synthesis of 2-vinyl tetrahydroquinoxalines