PHOSPHINOCYCLOPENTADIENYL ZIRCONIUM COMPLEXES IN SELECTIVE C-C BOND FORMATION

本文提出了制备和研究配合物（eta 5- C5 H5）（eta 5-C5 H4 P（C6 H5）2）ZrXY（X，Y烷基、卤化物、醇盐配体）作为 单核复合物与小，不饱和分子，然后允许 这些络合物经受所选底物的亲核攻击。 我们 预计这些配合物将导致新的方法，用于合成 酮、醛、醇和胺， Zr原子上的辅助配体X。 烷基络合物相当 易受不饱和极性分子如CO和 异腈进入Zr-C键。 在以前的工作中，我们已经观察到， 单核络合物（η 5-C5 H4 P（C6 H5）2）2 Zr（CH 3）Cl与CO反应， 形成易于进行亲核攻击的插入产物 分子内的磷配体和外部的 亲核试剂 CO键级被还原为单键， 过程和扭曲的四面体几何被发现周围的C原子 其与Zr、O、C和P结合。 C5 H5）（eta 5-C5 H4 P（C6 H5）2）ZrXY，将不能经历 分子内的路径和暴露只有一个面的四面体几何 (that与磷原子“反式”连接），以从磷原子亲核连接。 外部亲核试剂 因此，立体特异性在形成中是可能的。 具有插入的CO的新键;手性辅助基团X的使用可以 导致亲核产物形成的对映选择性 攻击 其他可能的产物包括获得的醛和酮。 在非氧化条件下和亚胺（来自 异腈）。 围绕这种试剂开发的方法可能会在以下方面得到应用： 天然产物和治疗剂前体的制备。 该项目将训练学生在所需的身体技能， 合成化学;在惰性气氛下操作化合物的能力 大气，光谱分析方法是他们的培训之一， 将收到。 在智力上，他们将被要求做出贡献 材料到他们的特定项目，从实验设计（设计 设备选择新的实验的适当方向），以 在书面和口头报告中介绍其结果（ 他们的学生同行和专业会议）。 这些努力将有助于 他们培养了成功的技术技能和自信心， 他们在健康科学方面的专业。

It is proposed to prepare and study the reactions of the complexes (eta5- C5H5)(eta5-C5H4P(C6H5)2)ZrXY (X,Y alkyl, halide, alkoxide ligands) as mononuclear complexes with small, unsaturated molecules and then allow these complexes to undergo nucleophilic attack by selected substrates. We expect that these complexes will lead to new methods for the synthesis of ketones, aldehydes, alcohols and amines by appropriate control of the auxiliary ligand X on the Zr atom. The alkyl complexes are quite susceptible to insertion of unsaturated polar molecules such as CO and isonitriles into the Zr-C bond. In previous work, we have observed that the mononuclear complex (eta5-C5H4P(C6H5)2)2Zr(CH3)Cl reacts with CO to form an insertion product which readily undergoes nucleophilic attack intramolecularly by the phosphorus ligand and also by external nucleophiles. The CO bond order is reduced to a single bond by this process and a distorted tetrahedral geometry is found around the C atom which is bound to Zr, O, C and P. The less symmetrical complexes, (eta5- C5H5)(eta5-C5H4P(C6H5)2)ZrXY, will not be able to undergo the intramolecular path and exposes only one face of the tetrahedral geometry (that "trans" to the phosphorus atom) to nucleophilic attach from an external nucleophile. Thus, stereospecificity is possible in the formation of new bonds with the inserted CO; use of a chiral auxiliary group, X, may lead to enantioselectivity in the formation of the product of nucleophilic attack. Other possible products include aldehydes and ketones obtained under non-oxidative conditions and imines (from insertion reactions of isonitriles). The methods developed around this reagent may find use in the preparation of natural products and precursors for therapeutic agents. This project will train students in the physical skills required in synthetic chemistry; the ability to manipulate compounds under inert atmospheres, spectroscopic methods of analyses are among the training they will receive. Intellectually, they will be required to contribute materially to their particular project, from experimental design (design of equipment to selection of appropriate direction of new experiments), to presentation of their results in written and spoken reports (both among their student peers and a professional meetings). These efforts will help them develop both the technical skills and self confidence to succeed in their professions in the health sciences.