Asymmetric Michael addition promoted by (R,R)-trans-1,2-diaminocyclohexane in ionic liquids

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• 作者：Vito Gallo ; Daniela Giardina-Papa ; Piero Mastrorilli ; Cosimo Francesco Nobile ; Gian Paolo Suranna and Yaquan Wang
• 关键词：Michael additions ; Chiral auxiliary ; Ionic liquids ; Enantioselectivity
• 刊名：Journal of Organometallic Chemistry
• 出版年：2005
• 期刊代码：64_0022328x
• 类别：ch
• 出版时间：2005
• 卷：690
• 期：15
• 页码：3535-3539
• 文件大小：130 K

摘要

In tetrafluoroborate based ionic liquids fair yields and enantiomeric excesses up to 91%were obtained in the Michael addition of ethyl cyclohexanone-2-carboxylate to methyl vinyl ketone, using (R,R)-trans-1,2-diaminocyclohexane as chiral auxiliary (37%mol/mol with respect to the donor). The presence of catalytic amounts of metal sources [Ni(OAc)₂ · 4H₂O, Co(acac)₂, FeCl₃ · 6H₂O, LaCl₃, Cu(OAc)₂ · H₂O] did not improve the activity, and, in some instances, caused a drop of enantioselectivity. Reactions carried out in the absence of any metal and with a Michael donor/diamine molar ratio of 20 allowed us to ascertain that the reaction can be performed catalytically.