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Updated: Jul 10, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Highly versatile enantioselective conjugate addition of Grignard reagents to alpha,beta-unsaturated thioesters
Beatriz Maciá Ruiz1, Koen Geurts, M Angeles Fernández-Ibáñez
1Department of Organic and Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Abstract:
Herein, we report efficient catalysts for the asymmetric copper-catalyzed conjugate addition of Grignard reagents to alpha,beta-unsaturated thioesters. MeMgBr adds to aromatic alpha,beta-unsaturated thioesters with excellent enantioselectivities and moderate to good yields using Josiphos/CuBr and Tol-BINAP/CuI complexes. The use of bulky Grignard reagents leads to unprecedented enantioselectivities in the 1,4-addition to a broad range of aromatic and aliphatic alpha,beta-unsaturated thioesters using Tol-BINAP/CuI. The highest enantioselectivities reported so far for the addition of Grignard reagents to crowded beta-substituted aliphatic substrates are achieved with Tol-BINAP/CuI.
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