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Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides

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Direct Catalytic Asymmetric Conjugate Addition of Benzofuran-3(2H)-Ones to α,β-Unsaturated Thioamides:

Sadhanendu Samanta¹, Hidetoshi Noda¹, Takumi Watanabe¹

¹Institute of Microbial Chemistry (BIKAKEN), Tokyo, 3-14-23 Kamiosaki Shinagawa-ku, Tokyo, 141-0021, Japan.

Angewandte Chemie (International Ed. in English)

|October 1, 2024

Abstract:

Rocaglaol, a representative flavagline, has attracted significant attention because of its unique chemical structure and biological activities. This paper reports a mild and scalable copper-catalyzed enantioselective conjugate addition of benzofuran-3(2H)-ones to α,β-unsaturated thioamides. This method allows for the concise synthesis of all possible stereoisomers of a key intermediate of rocaglaol and its derivatives in a highly diastereo- and enantioselective manner using different chiral phosphine ligands. Theoretical insights into the reaction mechanism and the origin of ligand-dependent diastereodivergence were obtained using density functional theory calculations.

Keywords:

asymmetric catalysis conjugate addition natural products thioamide total synthesis

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