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Updated: Jun 10, 2025

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Cinchona Organocatalyzed Enantioselective Amination for Quaternized Serines as Tertiary Amides
Phathutshedzo Masithi1, Ashlyn D Bhana1, Gerhard A Venter1
1Department of Chemistry, University of Cape Town, Rondebosch, Cape Town 7700, South Africa.
Abstract:
Herein, we describe a Cinchona-aminocatalyzed enantioselective α-hydrazination of an α-formyl amide for the production of protected quaternized serines as tertiary amides with ee's of generally >98% and ≤99% yields. The proposed TS model supported by density functional theory calculations involves a quinuclidinium ion Brønsted acid-assisted delivery of DtBAD, which occurs from the Re face of an H-bonded enaminone when using a 9S-cinchonamine catalyst, resulting in a hydrazide with the R-configuration as determined by X-ray analysis.
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