Development of Efficient Homogeneous Gold Catalysis

在化学系化学催化项目的支持下，加州大学圣巴巴拉分校的张黎明博士正在开发从金中提取的新催化剂。这些催化剂被用来加速有机分子上的化学反应，并对形成的产物进行非常精确的控制。这些催化反应将简单的分子转化为更复杂的分子，然后可以用作药物发现、生物医学研究和材料科学的基石。构建这些目标分子往往是整个合成过程中最困难的部分。所描述的研究是由本科生和研究生进行的，为他们作为下一代STEM劳动力做准备。张博士还参与了针对未被充分代表的少数民族和高中生的宣传活动。此外，张博士正在将黄金催化纳入本科实验室课程，让他的学生了解他们的研究所带来的产业效益。这项工作通过促进工业创新和培训高技术劳动力来促进美国的繁荣。C(SP3)-H键的官能化，特别是那些未被激活的官能化，具有很大的合成价值，因为它使得与药物或材料相关的分子的合成变得流线型，而不需要底物预先官能化。然而，由于反应性和选择性的问题，这一战略的实施具有挑战性，而且仍然不发达。张博士正在研究末端酮与金催化剂在亲电溴化试剂存在下反应生成的亚金亚乙烯的化学。然后，这些亚甲基配合物插入C-H键，形成5元或6元的溴环戊酮或溴环己酮。还研究了其他亲电试剂的使用，亚乙叉反应性的调节，以及插入更远的C-H键，因为这些变化提供了合成灵活性和获得一系列有价值的结构。张博士还在研究金催化剂对炔烃或烯的亲电攻击的活化作用。它们要么是与具有挑战性的亲核试剂发生的分子间反应，要么是与产生有价值的杂环的杂原子亲核试剂发生的分子内反应。使用带有手性膦或N-杂环卡宾配体的催化剂进行对映选择性催化也很有兴趣。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Catalysis Program of the Division of Chemistry, Dr. Liming Zhang of the University of California at Santa Barbara is developing new catalysts derived from gold. These catalysts are used to speed up chemical reactions on organic molecules with very precise control of the products formed. These catalysis reactions convert simple molecules to those of greater complexity that can then be used as building blocks in drug discovery, biomedical research, and materials science. The building these target molecules is often the most difficult part of the entire synthetic process. The research described is conducted by undergraduate and graduate students and prepares them as the next generation of the STEM workforce. Dr. Zhang is also involved in outreach efforts targeting underrepresented minorities and high school students. In addition, Dr. Zhang is incorporating gold catalysis into undergraduate laboratory courses, so that his students know of the industrial benefits of their research. This work advances the prosperity of the US by promoting innovation in industry and training of a highly technical workforce. The functionalization of C(sp3)-H bonds, especially those that are unactivated, is of great synthetic utility as it enables the streamlined synthesis of molecules of medicinal- or materials-relevance without substrate pre-functionalization. This strategy, however, is challenging to implement due to issues of reactivity and selectivity, and remains underdeveloped. Dr. Zhang is studying the chemistry of gold vinylidenes generated from the reaction of terminal ynones with gold catalysts in the presence of an electrophilic bromination reagent. These vinylidene complexes then insert into a C-H bond to form a 5- or 6-membered bromocyclopentenone or bromocyclohexenone. The use of other electrophilic reagents, the tuning of the vinylidene reactivity, and the insertion into more remote C-H bonds are also studied as these alterations provide synthetic flexibility and access to a range of valuable structures. Dr. Zhang is also studying the activation of alkynes or allenes towards electrophilic attack by gold catalysts. These are either intermolecular reactions with challenging nucleophiles, or in intramolecular reactions with heteroatom nucleophiles that produce valuable heterocycles. Enantioselective catalysis with catalysts that bear chiral phosphine or N-heterocyclic carbene ligands specifically tailored to the linear structures of gold(I) complexes are also of interest.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.