Stable Simple Enols. Resolution of Chiral 1-[9‘-(2‘-Fluoroanthryl)]-2,2-Dimesitylethenol. A Different Racemization Mechanism for the Enol and its Acetate<sup>1</sup>
作者:Elimelech Rochlin、Zvi Rappoport
DOI:10.1021/jo020497q
日期:2003.1.1
expected for a rotational betabeta'-2-ring flip process in a vinyl propeller and the racemization is unaffected by added TFA, Et3N, and EtOD. Although 3 racemizes almost 350 times faster, the racemization is catalyzed by TFA and shows bell-shape catalysis by Et3N and a KIE in a partially deuteriated solvent. From this and the DNMR data, it is concluded that 3 does not racemize via a rotational betabeta'-2-ring
手性1- [9'-(2'-甲氧基蒽基)]-2,2-二甲基间苯三酚(2),1- [9'-(2'-氟蒽基)]-2,2-二甲基间苯三酚(3)和1-合成了[9'-(2'-氟蒽基)]-2,2-二聚乙烯乙酸乙烯酯(4),研究了它们在C6D5NO2中的DNMR行为。将3和4在直链淀粉三(3,5-二甲基苯基氨基甲酸酯)HPLC柱上拆分为它们的对映异构体。醋酸盐4在DeltaG(e)(++),DeltaH(e)(++)和DeltaS(e)(++)值分别为26.2、27.6 kcal mol(-)(1)和4.3的溶液中缓慢消旋分别对乙烯基螺旋桨中的旋转betabeta'-2-环翻转过程而言是预期的eu,外消旋化不受添加的TFA,Et3N和EtOD的影响。尽管3的消旋速度快了350倍,但消旋作用由TFA催化,在部分氘代的溶剂中由Et3N和KIE呈钟形催化。从该数据和DNMR数据得出的结论是3不会通过旋转的betabeta'-2-ring