From Molecular Iodine to Chiral Catalysts - Systematic Applications of Halogen-Bonding in Organocatalysis

这一研究将推动卤键研究领域的发展，并将其系统地应用于有机合成中。具体而言，我们将专注于立体选择性卤素键催化反应的发展和所需的手性催化剂的设计。迄今为止，卤键已成功地应用于包括有机催化在内的化学领域，但由卤键引起的立体选择性转化却很少。为了缩小这一差距，我们结合联合收割机经典的物理有机和光谱技术和计算研究与合成实验。我们将确定手性添加剂，能够络合分子碘，最简单的卤素键供体之一，创造一个手性环境，结果在对映选择性转化。此外，我们将为不同的卤素键图案，使我们能够确定有前途的候选人的催化构建一个刘易斯酸度标度。这些催化剂将补充目前使用的脯氨酸或脯氨醇衍生的结构。我们证明了这些新发现的催化剂在重要的有机催化转化中的活性。因此，我们的研究一方面通过引入新的基序为有机催化领域提供了一个新的视角。另一方面，物理有机分析将提供深入了解这种未探索的非共价相互作用的关键方面。

The research will advance the field of halogen bonding and its systematic application in organic synthesis. Specifically, we will focus on the development of stereoselective halogen-bond-catalyzed reactions and the design of the required chiral catalysts. So far, halogen bonding has successfully been employed in different field of chemistry including organic catalysis, but stereoselective transformations caused by halogen bonds are scarce. To close this gap, we combine classical physical-organic and spectroscopic techniques and computational investigations with synthetic experiments. We will identify chiral additives that are capable of complexing molecular iodine, one of the simplest halogen-bond donors, to create a chiral environment that results in enantioselective transformations. Furthermore, we will construct a Lewis-acidity scale for different halogen-bond motifs that allows us to identify promising candidates for catalysis. Those catalysts will complement the currently employed proline- or prolinol-derived structures. We demonstrate the activity of these newly identified catalysts in important organocatalytic transformations.Therefore, our investigations offer on the one hand a new perspective on the field of organocatalysis by the introduction of new motifs. On the other hand, the physical-organic analysis will provide deep insights into crucial aspects of this unexplored noncovalent interaction.