Chiral Biaryl Heterocycles as Ligands for Enantioselective Catalysis

在这个由NSF化学部化学催化计划资助的项目中，佛罗里达大学的Aaron Aponick教授正在开发一类新的联芳基配体，该配体将通过改进催化剂来扩大目前最先进的化学合成能力。 精细化工行业每年有数十亿美元的市场，严重依赖催化作为生产手段。 因此，全球需要开发新的催化剂和配体，特别是对于其中重要的是能够修饰结构以微调反应结果的对映选择性反应。该研究追求具有增强的反应性和选择性的配体和催化剂设计。这项工作的更广泛的影响源于对基础科学的理解和对更先进系统的应用。 开发的工具广泛适用于各种环境，并提供了一个肥沃的环境，以培养学生在国家的最先进的技术，为未来的学术和工业的努力。当地一家购物中心的化学日--一个信息丰富的教育推广项目--将在一个以广泛的人口统计而闻名的公共论坛上展示科学。 其目的是打破公众对科学的一些认知障碍。拟议的研究旨在将杂环化合物（一类非常容易制备的化合物）纳入手性联芳基支架中。这类新的联芳基配体利用了阻转异构的原始概念，其中π堆叠增加了旋转的势垒，并使得能够在手性联芳基配体中引入富电子的5元环杂环。 所得配体具有不同于已知配体的空间和电子性质，并且容易通过高度收敛的制备路线进行修饰。联芳基配体可能能够以可预测和可调节的方式彻底改变系统的催化性质。

In this project funded by the Chemical Catalysis program of the NSF Division of Chemistry, Professor Aaron Aponick of the University of Florida is developing a new class of biaryl ligands that will expand the current capabilities of state-of-the-art chemical synthesis through improved catalysis. The fine chemical industry has a multi-billion dollar annual market that heavily relies on catalysis as a means of production. As such, there is a global need for the development of new catalysts and ligands, especially for enantioselective reactions where it is important to be able to modify the structure to finely tune the reaction outcome. This research pursues ligand and catalyst designs with enhanced reactivity and selectivity. The broader impacts of this work stem from gaining an understanding of the fundamental science and application to more advanced systems. The tools developed are widely applicable in a variety of settings and also provide a fertile environment to train students in state-of-the-art techniques for future academic and industrial endeavors. Chemistry Day at a local mall--an informative and educational outreach program--will present science in a public forum known for its wide demographics. The intention is to break down some of the perceived barriers with science among the general public.The proposed research aims to incorporate heterocycles, a class of compounds that are extremely easy to prepare, into a chiral biaryl scaffold. This new class of biaryl ligands capitalizes on an original concept for atropisomerism whereby pi-stacking increases the barrier to rotation and enables the incorporation of electron-rich, 5-membered ring heterocycles in chiral biaryl ligands. The resulting ligands have different steric and electronic properties than known ligands and are readily modified by a highly convergent preparative route. Biaryl ligands may be able to drastically alter the catalytic properties of a system in a predicable and tunable manner.