Reactions and Stereochemistry of Organometallic Compounds Related to Asymmetric Synthesis and Catalytic Activity

约翰·W·法勒博士，耶鲁大学化学系，由无机化学、生物无机化学和金属有机化学计划资助，从事与不对称和区域选择性合成以及使用金属络合物的催化相关的研究。将开发新的不对称合成策略，其基础是使用廉价的手性毒药处理的现成的外消旋前催化剂。该毒药选择性地使外消旋混合物的一个对映体失活。剩余的活性对映体用于催化不对称反应。这一一般策略已被证明用于不对称氢化和Lewis酸催化的Diels-Alder反应。将开发更有效的毒药，并将其应用于制备用于广泛不对称反应的手性催化剂。将探索由含有不同手性配体的双金属化合物组成的假对映体络合物。半活性配体将被用于控制催化中间体的立体化学。手性16电子中间体的外消旋可能会降低不对称催化剂的选择性。这一消旋过程和控制它的方法也将被研究。与其镜像不同的对象(例如，左手手套与右手手套相比)称为手性。许多医药和农业化学品是手性的，通常两个镜像分子中只有一个是有效的。由于很难获得单一的镜像，因此这种分子的生产是当代化学的一个重要目标。在这个项目中，解决“不对称合成”问题的新策略将应用于广泛的反应，并将开发新的、更经济的重要分子的制备方法。除了化学研究，这个项目还有一个重要的目标，就是培养年轻的金属催化和不对称合成领域的科学家。

Dr. John W. Faller, Chemistry Department, Yale University, is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program for studies related to asymmetric and regioselective synthesis and catalysis using metal complexes. New strategies will be developed for asymmetric synthesis based on the use of readily available racemic precatalysts treated with an inexpensive chiral poison. The poison selectively deactivates one enantiomer of the racemic mixture. The remaining active enantiomer is used to catalyze an asymmetric reaction. This general strategy has been demonstrated for asymmetric hydrogenations and Lewis acid-catalyzed Diels-Alder reactions. More effective poisons will be developed and will be applied to the preparation of chiral catalysts for a broad range of asymmetric reactions. Pseudo-enantiomeric complexes, which are composed of bimetallics containing different chiral ligands, will be explored. Hemilabile ligands will be used to control the stereochemistry in catalytic intermediates. The racemization of chiral 16 electron intermediates can potentially decrease the selectivity of asymmetric catalysts. This racemization process and methods of controlling it will also be studied. An object which is not the same as its mirror image (e.g. a left compared to a right handed glove) is said to be chiral. Many pharmaceutical and agricultural chemicals are chiral and often only one of the two mirror image molecules is effective. Since it is difficult to obtain a single mirror image, the production of such molecules is an important goal in contemporary chemistry. In this project new strategies toward solving the problem of "asymmetric synthesis" will be applied to a broad range of reactions and new, more economic preparations of important molecules will be developed. In addition to the chemical research, this project has the important objective of training young scientists in the areas of metal catalysis and asymmetric synthesis.