Photochemical deracemization catalyzed by chiral triplet sensitizers with a lactam binding motif

具有内酰胺结合基序的手性三重态敏化剂催化的光化学去消旋化

• 批准号: 427465615
• 负责人: Professor Dr. Thorsten Bach
• 金额: --
• 依托单位: Lehrstuhl für Organische Chemie I
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/427465615?language=en
• 关键词: Photochemical; deracemization; catalyzed; chiral; triplet

A deracemization is a process in which a racemic mixture is selectively and ideally quantitatively converted into a specific enantiomer. Due to the fact that enantiomers have identical standard enthalpies of formation a deracemization is impossible in a thermal equilibrium mediated by a chiral catalyst. However, deracemization reactions can be performed photochemically with a chiral triplet sensitizer that displays a hydrogen bonding motif (lactam) and acts as catalyst. Possible substrates for this transformation include allenes, cycloalkanes, sulfoxides, and 1,1'-biaryls. Experimentally, the most relevant parameters are to be identified which are responsible for a high enantioselectivity. To this end, it is also planned to modify the chromphore of the sensitizer, a thioxanthone or xanthone, by appropriate substitution and to adapt its triplet energy to the individual substrates. The major focus is on method development but the work will be accompanied by photophysical studies and will be directed towards synthetic applications.

去外消旋化是其中外消旋混合物选择性地且理想地定量转化为特定对映体的过程。由于对映异构体具有相同的标准形成速率，因此在手性催化剂介导的热平衡中不可能进行去外消旋化。然而，去外消旋化反应可以用显示氢键基序（内酰胺）并充当催化剂的手性三重态敏化剂光化学地进行。这种转化的可能底物包括联烯、环烷烃、亚砜和1，1 '-联芳基。实验上，最相关的参数是要确定负责高对映体选择性。为此，还计划通过适当的取代来修饰敏化剂的发色团，噻吨酮或吨酮，并使其三重态能量适应各个底物。主要重点是方法开发，但工作将伴随着地球物理研究，并将针对合成应用。