8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P1.28Fri 911:10-14:00Proline based chiral ionic liquids for chiral synthesisKaoru Nobuoka, 1 Satoshi Kitaoka, 1 and Yuichi Ishikawa 11 Oita University, 700 Dannoharu, 870-1192, Oita, JapanIonic liquids have various properties that make them attractive for application. The high designabilityof ionic liquids gives functional possibilities. Among so-called task-specific ionic liquids, chiralionic liquids have received considerable attention as an enantioselective catalyst and a medium forchiral synthesis or chiral extraction. Thus, we designed and synthesized novel chiral ionic liquidsstarting from L-proline which is a natural chiral amino acid. The proline based ILs show very lowmelting point (−73 ◦ C) and viscosity (124 cP at 25 ◦ C). We investigated the catalytic activity ofthe proline based ionic liquids for the asymmetric Michael addition of cyclohexanone to trans - b-nitrostyrene. The proline based chiral ionic liquid can give high stereo- and enantio- selectivities(syn/anti 92/8, 85%ee), but the yield was low (52%). Acid additives improve the yields withoutlowering the selectivities (88% : TFA, 92% : salicylic acid), and the ionic liquids can be recycledat least three times without significant loss of activity.28