N-Spiro Chiral Quaternary Ammonium Bromide Catalyzed Diastereo- and Enantioselective Conjugate Addition of Nitroalkanes to Cyclic α,β-Unsaturated Ketones under Phase-Transfer Conditions

Takashi Ooi, Saki Takada, Shingo Fujioka and Keiji Maruoka*

*Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan, Email: maruokakuchem.kyoto-u.ac.jp

T. Ooi, S. Takada, S. Fujioka, K. Maruoka, Org. Lett., 2005, 7, 5143-5146.

DOI: 10.1021/ol0517170

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Abstract

An N-spiro C₂-symmetric chiral quaternary ammonium bromide efficiently catalyzed the conjugate addition of various prochiral nitroalkanes to cyclic α,β-unsaturated ketones under solid-liquid phase-transfer conditions to afford the corresponding γ-nitro ketones in excellent yields with high levels of diastereo- and enantiocontrol.

see article for more examples

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Practical Stereoselective Synthesis of β-Branched α-Amino Acids through Efficient Kinetic Resolution in the Phase-Transfer-Catalyzed Asymmetric Alkylations

T. Ooi, D. Kato, K. Inamura, K. Ohmatsu, K. Maruoka, Org. Lett., 2007, 9, 3945-3948.

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Key Words

Michael Addition, Conjugate Addition, Nitro compounds

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ID: J54-Y2005-1870