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Updated: May 13, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Stereodefined trisubstituted enolates as a unique entry to all-carbon quaternary stereogenic centers in acyclic
Yury Minko1, Morgane Pasco, Lukas Lercher
1The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology, Haifa, Israel.
Abstract:
This protocol describes a new approach for the preparation of stereodefined trisubstituted chiral enolate species, avoiding conventional asymmetric enolization of carbonyl compounds. This protocol was developed as a single-flask synthetic sequence and therefore does not require isolation or purification of intermediate compounds. The sequence starts from a regioselective carbocupration reaction of readily accessible chiral ynamides; this is followed by oxidation of the generated vinylcuprate with a commonly available oxidizing reagent (tert-butyl hydroperoxide) in order to generate an enolate that completely retains its configuration. This synthetic protocol has been applied to the preparation of aldol and Mannich-type adducts. The procedure reported here requires a simple reaction setup commonly available in all synthetic laboratories and takes ∼6 h for completion and 2 h for isolation and purification. Final products are valuable diastereomerically and enantiomerically enriched building blocks for organic synthesis containing all-carbon quaternary stereocenters in acyclic systems.
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