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Updated: May 7, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
List-Barbas-Mannich reaction catalyzed by modularly designed organocatalysts
Sandun Perera1, Debarshi Sinha, Nirmal K Rana
1Department of Chemistry, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas 78249-0698, United States.
Abstract:
The List-Barbas-Mannich reaction of ethyl (p-methoxyphenylimino)acetate (p-methoxyphenyl = PMP) with unmodified aldehydes or ketones catalyzed by modularly designed organocatalysts (MDOs) that are self-assembled from proline and cinchona alkaloid thioureas (such as a quinidine-derived thiourea) produces the corresponding γ-oxo-α-amino acid derivatives in high yields and excellent stereoselectivities. No solvent is necessary for this reaction. Aldehydes are especially good substrates for this reaction: The reaction takes only a few minutes to yield the corresponding List-Barbas-Mannich products in excellent dr (up to >99:1) and ee values (up to >99% ee).
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