Grant-in-Aid for Specially Promoted Research: Design of High-Performance Organocatalysts for the Application to Fine Organic Synthesis SitemapJapanese
  • Maruoka Group, Department of Chemistry, Graduate School of Science, Kyoto University
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Research [Base Organocatalyst]

 As base organocatalysts, cinchona alkaloids and its derivatives were often used in asymmetric reactions. Furthermore, cinchona alkaloid-derived quaternary ammonium salts, which were prepared by N-alkylation of cinchona alkaloids, worked as effective chiral phase-transfer catalysts. Our group has developed originally designed axially chiral phase-transfer catalysts (Scheme 1), and the first-generation catalyst (S,S)-1 (Maruoka Catalyst®) can be designed in 1999. Later, even more efficient phase-transfer catalyst (S)-2 (Simplified Maruoka Catalyst®) can be designed by introducing a combinatorial design approach, which is found to be a quite useful for further design of various types of mono- and bifunctional phase-transfer catalysts such as (S)-3, and many efficient asymmetric reactions under phase-transfer conditions using these catalysts have been developed. Although it is believed for a long period that base additives such as alkaline metal hydroxide or carbonate are essential to promote the phase-transfer reaction, we recently discovered that even without any base additives enantioselective phase-transfer reactions efficiently proceeded in water-rich biphasic solvent (Scheme 2). This simple reaction system has a large possibility for the development of environmentally-benign practical reactions.

Scheme 1

Scheme 2