GROUP VIA METAL COMPLEXES IN SYNTHESIS

描述：这项提议的主要目标是发展 烯烃和双烯基受控官能化新方法 关于过渡金属基团的有机金属化学。这个 01年至04年的具体重点将是操纵 对-烯丙基和二烯-钼络合物；其他通过金属的基团是 目前还没有考虑，但预计初步 他们的化学结果可以在赠款期间产生。 开环pi-烯丙基-Mo(CO)_2Cp体系在稳定a~+中的作用 将研究邻近的碳负离子。以前观察到的不可逆性 这些碳负离子的重新排列将允许构建 立体化学定义的具有重要结构的烯烃亚基 许多生物重要分子的特征。化学中的化学 环状pi-烯丙基-钼配合物生成的碳离子 作为环己二烯-钼的外部亲核加成 将作为建造的方法进行评估 第四纪碳中心。将研究区域控制的方法， 导致合成重要亚基的新方法 石蒜科生物碱。内部碳亲核加成到 将对二烯-钼配合物进行研究，从而得出 螺环和其他复杂环系的构建。这 将是亲电环化反应的第一个一般性研究 双烯化合物，将在快速发展的地区开辟新天地 使用有机金属络合物的有机合成。手性药物的使用 与二烯和烯丙基溴化物相连的助剂 光学纯的联烯丙基和二烯钼配合物的合成 将进行研究，以期允许上述所有 用于不对称有机合成的方法学。

DESCRIPTION: The principal goal of this proposal is the development of new methods for controlled functionalization of alkenes and dienes based on organometallic chemistry involving Group VIA transition metals. The specific focus in the 01 through 04 years will be on the manipulation of p-allyl- and diene-molybdenum complexes; other Group VIA metals are not considered at this time, but it is anticipated that preliminary results on their chemistry can be generated during the grant period. The role of an acyclic pi-allyl-Mo(CO)2Cp system in stabilizing a neighboring carbanion will be studied. Previously observed irreversible rearrangements of these carbanions will allow the construction of stereochemically defined olefinic subunits that are important structural features of many biologically important molecules. The chemistry of carbanions generated from cyclic pi-allyl-molybdenum complexes, as well as external nucleophile additions to cyclohexadiene-molybdenum complexes, will be evaluated as methodology for the construction of quaternary carbon centers. Methods for regiocontrol will be examined, leading to new approaches for the synthesis of important subunits of Amaryllidaceae alkaloids. Internal carbon nucleophile additions to diene-molybdenum complexes will be studied, leading to methodology for the construction of spirocyclic and other complex ring systems. This will be the first general study of annulation reactions of electrophilic diene complexes and will break new ground in the rapidly developing area of organic synthesis using organometallic complexes. The use of chiral auxiliaries attached to dienes and allylic bromides, to effect the synthesis of optically pure pi-allyl- and diene-molybdenum complexes, will be studied in anticipation of allowing all of the aforementioned methodology to be applied in asymmetric organic synthesis.