RUI: Asymmetric catalytic hydroamination of aminoallenes by chiral tantalum cyclopentadienyl-amide-alkoxide complexes

化学催化项目支持哈维·穆德学院的亚当·R·约翰逊教授，他将研究对映体选择性氢胺化催化和丙交酯的立体选择性聚合，这是当前感兴趣的两个领域。这项拟议的研究将考察氢胺化反应，这是一个跨越碳-碳多键的氮-氢键的加成。这种原子经济性很高的方法生产的取代胺是有价值的合成靶标。许多金属都能催化这一反应，但目前还没有通用的方法。双齿氨基醇配体的钛配合物用于氨基烯的不对称氢胺化反应具有良好的区域选择性，但立体选择性较差。相应的钽配合物最近被证明具有更强的立体选择性。PI和他的同事们将合成与手性氨基醇相连的新型手性配体并进行快速筛选，合成并研究与这些手性配体形成的钛和钽配合物，以及与连接和未连接的配体进行催化氢胺化反应。手性氨基醇络合物还将用于聚合生物衍生单体丙交酯。作为一种基于可再生原料的可生物降解聚合物，开发高效的催化剂合成不同规整度的聚乳酸具有重要意义。如果成功，这两个领域的研究都将产生革命性的影响。在国家科学基金会化学部化学催化计划的支持下，亚当·R·约翰逊博士对氢胺化的持续研究将对金属有机化学前沿的教学产生影响，并将扩展到更广泛的无机化学教育工作者社区。这项研究的结果将影响约翰逊教授在哈维穆德学院教授无机和有机金属化学，以及他参与美国国家科学基金会资助的Viper项目(www.ION icviper.org)，这是一个无机化学在线教学和社交网站。本科生将有机会研究合成有机金属化学中的现代问题，合成和提纯配体和络合物，生长晶体，并执行催化反应。学生将获得创造性解决问题和团队合作的经验，并将在当地和美国化学学会的全国会议上展示他们的研究成果。

The Chemical Catalysis Program supports Professor Adam R. Johnson at Harvey Mudd College who will examine enantioselective hydroamination catalysis and stereoselective polymerization of lactide, which are two areas of significant current interest. The proposed research will examine the hydroamination reaction, which is the addition of a nitrogen-hydrogen bond across a carbon-carbon multiple bond. The highly atom-economical method produces substituted amines that are valuable synthetic targets. A number of metals catalyze this reaction but there are no general methods for it. The asymmetric hydroamination of aminoallenes using titanium complexes of bidentate aminoalcohol ligands gives good regioselectivity, but poor stereoselectivity. The corresponding tantalum complexes have recently been shown to be more stereoselective. The PI and his coworkers will synthesize novel chiral ligands tethered to a chiral amino-alcohol and rapidly screen them, synthesize and study titanium and tantalum complexes with these chiral ligands, and perform catalytic hydroaminations with tethered and untethered ligands. The chiral amino-alcohol complexes will also be used to polymerize the biologically derived monomer, lactide. As a biodegradable polymer based on a renewable feedstock, the development of efficient catalysts for the synthesis of polylactide with varying tacticity is of great importance. If successful, both areas of research will have a transformative impact.With the support of the Chemical Catalysis Program in the Chemistry Division at the National Science Foundation, Dr. Adam R. Johnson's continued research on hydroamination will have an impact on teaching at the frontiers of organometallic chemistry and will extend to a wide community of inorganic chemistry educators. The results from this research will affect Professor Johnson's teaching of inorganic and organometallic chemistry at Harvey Mudd College and his participation in the NSF-funded VIPEr project (www.ionicviper.org), an on online teaching and networking site for inorganic chemistry. Undergraduate students will have an opportunity to examine modern problems in synthetic organometallic chemistry, synthesize and purify the ligands and complexes, grow crystals, and perform the catalytic reactions. Students will gain experience in creative problem solving and teamwork, and will present their research results both locally and at a national American Chemical Society Meeting.