Organic Transformations of Coordinated Ligands

无机，生物无机和有机金属化学项目的重点是有机分子的化学转化，当这些分子与金属结合时发生化学转化。这些反应与在均相或非均相过渡金属催化剂上发生的有机化学反应密切相关，包括工业化学中一些最重要的反应。炔配体和-2-烯基配体是等圆的，构成共轭酸碱对。烯酸酯化学的核心去质子化/烷基化反应序列可以用带有-氢的金属结合4电子给体炔配体重复。在炔的β碳上脱质子形成亲核的β -2-烯基配体，适于在β碳上进行亲电加成和醛醇型缩合反应。将探讨利用金属碎片在这种反应中提供区域和立体控制。还需要研究的是，乙醛与烯基加成形成伽马醇的可能性，可能导致消除，形成通过炔三键结合的共轭炔，并准备进行1,4共轭加成反应。功能化炔的释放有望为构建各种有机构建块提供强大的载体。由于预计-2-亚氨基酰基和-2-乙烯基配体在-碳位置也是酸性的，因此将分别通过亲核配位阴离子和-2-烯中间体对这些配体进行精化。继通过连续氢化物加成和质子化反应成功地逐步还原金属结合腈之后，将尝试非对映选择性腈还原，并探索金属中心构型的保留，以开发手性胺合成的催化剂。

The focus of this project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is chemical transformations of organic molecules which occur while these molecules are bound to a metal. These reactions are intimately related to reactions of organic chemicals which occur on homogeneous or heterogeneous transition metal catalysts, and include some of the most important reactons in industrial chemistry. Alkyne ligands and eta-2-allenyl ligands are isolobal and constitute a conjugate acid-base pair. The deprotonation/alkyl- ation reaction sequence which is central to enolate chemistry can be duplicated with metal bound 4-electron donor alkyne ligands bearing a beta-hydrogen. Deprotonation at the beta carbon of the alkyne forms a nucleophilic eta-2-allenyl ligand suitable for electrophilic addition and aldol type condensation reactions at the beta carbon. The use of the metal fragment to provide both regio and stereocontrol in such reactions will be explored. Also to be investigated is the possibility that the formation of a gamma alcohol by aldehyde addition to the allenyl could lead to elimination to form a conjugated enyne bound through the alkyne triple bond and poised for 1,4-conjugate addition reactions. Release of the functionalized alkyne is expected to provide a powerful vehicle for building diverse organic building blocks. Since eta-2-iminoacyl and eta-2-vinyl ligands are expected to be acidic at the beta carbon position also, elaboration of these ligands via nucleophilic coordinated anion and eta-2-allene intermediates, respectively, will be pursued. Following on the successful stepwise reduction of metal bound nitriles by successive hydride addition and protonation reactions, diastereoselective nitrile reductions will be attempted, and the retention of configuration at the metal center will be probed in an effort to develop a catalyst for chiral amine syntheses.