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

化学催化计划支持教授亚当R。约翰逊在哈维马德学院谁将研究对映选择性加氢胺化催化和立体选择性聚合的丙交酯，这是两个领域的重大当前的兴趣。拟议的研究将检查加氢胺化反应，这是在碳-碳多重键上添加氮-氢键。高度原子经济的方法产生取代的胺，是有价值的合成目标。许多金属催化剂催化该反应，但没有通用的方法，使用双齿氨基醇配体的钛配合物的氨基联烯的不对称氢胺化提供了良好的区域选择性，但较差的立体选择性。相应的钽配合物最近已被证明是更立体选择性。PI和他的同事将合成新型手性配体与手性氨基醇连接并快速筛选它们，合成和研究这些手性配体的钛和钽配合物，并与连接和未连接的配体进行催化氢胺化。手性氨基-醇复合物也将用于使生物衍生的单体丙交酯稳定。作为一种以可再生原料为基础的可生物降解聚合物，开发高效的催化剂合成具有不同立构规整度的聚乳酸具有重要意义。如果成功的话，这两个领域的研究将产生变革性的影响。约翰逊对氢化胺化的持续研究将对有机金属化学前沿的教学产生影响，并将扩展到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·穆德学院的无机和有机金属化学教学，以及他参与NSF资助的VIPer项目（www.ionicviper.org），这是一个在线教学和无机化学网络网站。本科生将有机会研究合成有机金属化学中的现代问题，合成和纯化配体和配合物，生长晶体，并进行催化反应。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.