Chiral protic imidazolium salts with a (−)-menthol fragment in the cation: synthesis, properties and use in the Diels–Alder reaction
作者:Ewa Janus、Marcin Gano、Joanna Feder-Kubis、Jacek Sośnicki
DOI:10.1039/c7ra12176h
日期:——
in commonly used solvents, thermal properties including phase transition temperatures, and thermal stability were also determined. Three of the synthesized tertiary salts (Cl, PF6 or OTf anion) were crystalline solids; 1-H-3-[(1R,2S,5R)-(−)-menthoxymethyl]-imidazolium bis(trifluoromethylsulfonyl)imide, (−)[H-Ment-Im][NTf2] was a liquid at room temperature. The chiral protic salts were used in a Diels–Alder
新的手性质子咪唑鎓盐在阳离子中含有 (1 R ,2 S ,5 R )-(-)-薄荷醇取代基和四种不同的阴离子(氯离子、六氟磷酸根、三氟甲磺酸根和双(三氟甲基磺酰)亚胺)被有效地制备和广泛表征. 进行了详细的 NMR 分析,并讨论了作为结合阴离子函数的咪唑鎓阳离子的质子和碳的化学位移的比较。还测定了比旋光度、在常用溶剂中的溶解度、热性能(包括相变温度)和热稳定性。三种合成的叔盐(Cl、PF 6或OTf阴离子)是结晶固体;1 -H-3-[(1 R ,2 S ,5 R )-(-)-薄荷氧基甲基]-咪唑鎓双(三氟甲基磺酰基)亚胺,(-)[H-Ment-Im][NTf 2 ]在室温下为液体。手性质子盐在 Diels-Alder 反应中用作测试反应,并将结果与阳离子中具有相同手性取代基的非质子手性离子液体 (1 R ,2 S ,5 R )-(- )-薄荷醇与双(三氟甲基磺酰基)亚胺阴离子。Diels-Alder