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

John W. Faller博士，耶鲁大学化学系，由无机、生物无机和有机金属化学项目资助，研究不对称和区域选择性合成以及金属配合物催化。将开发新的不对称合成策略，基于使用易于获得的外消旋配体，然后用廉价的手性毒性处理，选择性地使外消旋混合物的一个对映体失活。剩余的配体对映体将用于制备手性金属催化剂。这种一般策略已被证明为不对称氢化反应，并将推广到许多其他系统，包括一系列钛醇盐催化反应。更有效的毒物将被开发出来，并将应用于制备手性催化剂，用于广泛的不对称反应，这些反应通常使用由对映异构纯膦配体制备的贵金属催化剂。在二聚体为活性物质的反应中，传统的方法涉及对映体单体的二聚化。将探讨通过使用含有不同手性配体的双金属组成的伪对映体配合物来提高对映体选择性的可能性。半可溶配体将用于控制催化中间体中的立体化学反应，并为烯丙基加成醛制备同丙烯醇提供化学计量试剂。一个与其镜像不一样的物体（例如左手的手套与右手的手套相比）被称为手性的。许多药物和农业化学品是手性的，通常只需要两个镜像分子中的一个。由于很难获得单一的镜像，因此这种分子的产生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、更经济的重要分子制备方法。除化学研究外，该项目还具有培养金属催化和不对称合成领域的青年科学家的重要目标。

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 ligands followed by treatment with an inexpensive chiral poison to selectively deactivate one enantiomer of the racemic mixture. The remaining ligand enantiomer will be employed to prepare chiral metal catalysts. This general strategy has been demonstrated for asymmetric hydrogenations and will be extended to a number of other systems including a series of titanium-alkoxide catalyzed reactions. More effective poisons will be developed and will be applied to the preparation of chiral catalyst for a broad range of asymmetric reactions that have conventionally used noble metal catalysts prepared from enantiomerically pure phosphine ligands. In reactions where dimers are active species, the conventional approach has involved the dimerization of enantiomeric monomers. The possibility of enhancing enantioselectivity through the use of 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 and to provide stoichiometeric reagents for preparation of homoallylic alcohols by allyl addition to aldehydes. 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 desired. 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 scientist in the areas of metal catalysis and asymmetric synthesis.