Tetrahydropyran-Based Hybrid Dipeptides as Asymmetric Catalysts for Michael Addition of Aldehydes to β-Nitrostyrenes

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• 作者：Jorge Borges-Gonzá ; lez ; André ; s Feher-Voelger ; Fernando Pinacho Crisó ; stomo ; Ezequiel Q. Morales and Tomá ; s Martí ; n
• 刊名：Advanced Synthesis & Catalysis
• 出版年：2017
• 出版时间：February 20, 2017
• 年：2017
• 卷：359
• 期：4
• 页码：576-583
• 全文大小：1482K
• ISSN：1615-4169

文摘

A new series of hybrid dipeptide-like organocatalysts based on pyranoid ϵ- or ζ-amino acids and proline have been prepared for the asymmetric Michael addition of aldehydes to β-nitrostyrenes. The reaction proceeds under mild conditions to afford a wide range of γ-nitroaldehydes with up to 98% yield and up to 96% ee. These dipeptides are bifunctional organocatalysts, with a proline at the N-terminus and a carboxylic acid at the C-terminus. The tetrahydropyran unit embedded in the ϵ- or ζ-amino acid induces a well-defined conformation that is responsible for the catalysis. These dipeptides represent a new type of organocatalyst with a large number of possibilities to modulate their reactivity and selectivity.