SYNTHETIC UTILITY OF ELECTROPHILIC METAL PI-COMPLEXES

提出了一项研究计划，其主要目标是 开发综合有用的方法，主要源于 亲电金属PI-络合物(炔丙基)Co-2(CO)6(1)， (烯丙基)Fe(CO)-4(2)和(二烯)Co(CO)L-3(3)。以前的工作有 建立了大量碳的简单、区域选择性偶联 具有配合物1和几个衍生物的亲核剂。这项建议 试图研究立体化学，并利用这些新的变种 选择性、代表性生物活性化合物合成中的反应 化合物和关键中间体，包括海洋大环乙炔 抗生素、金刚烷和鬼臼倍半萜(细胞毒性， 抗肿瘤)和带有修饰侧链的类固醇(性激素， 抗肿瘤药物、维生素代谢物)。 2与所选化合物反应的初步研究 通常指向高区域和立体选择性的亲核试剂 偶联反应，最近发现了铁催化的烯丙基烷基化反应。 未来的努力将集中在：1)确定这些铁的范围 与亲核试剂、底物和它们的 对区域选择性和立体选择性的影响；2)比较这些反应 2和(n-2-烯丙基X)Fe(CO)4； 以及3)检查与烯丙基亲核试剂的反应，作为区域和立体- 选择性异戊二烯基化方法学。 最后，基础的“开创性”研究的准备和 亲电的n-4-二烯配合物的反应性，3将被进行。 主要感兴趣的问题包括区域和立体选择性 亲核分子对3的攻击。综合用途的开发 来自这些研究的方法可能在未来的 建造复杂的天然产物。

A research program is proposed which has as its primary objective the development of synthetically useful methodologies derived primarily from the electrophilic metal Pi- complexes (propargyl)Co-2(CO)6+ (1), (allyl)Fe(CO)-4+ (2), and (diene)Co(CO)L-3+ (3). Previous work has established the facile, regioselective coupling of numerous carbon nucleophiles with the complexes 1 and several derivatives. This proposal seeks to examine the stereochemistry and to utilize new variations of these reactions in the synthesis of selected, representative biologically active compounds and key intermediates including marine acetylenes, macrocyclic antibiotics, guiane and pseudoguiane sesquiterpenes (cytotoxic, anti-tumor), and steroids with modified side chains (sex hormones, anti-tumor agents, vitamin metabolites). Following preliminary studies of the reactions of 2 with selected nucleophiles which point towards generally high regio- and stereoselective couplings, iron-catalyzed allylic alkylation has recently been discovered. Future efforts will focus on: 1) defining the scope of these iron catalyzed reactions with respect to nucleophiles, substrates, and their influence on regio- and stereoselectivity; 2) comparing these reactions with their stoichiometric counterparts, those of 2 and (n-2-allylX)Fe(CO)4; and 3) examining reactions with allyl nuleophiles as a regio- and stereo- selective isoprenylogation methodology. Finally, fundamental "ground-breaking" studies of the preparation and reactivity of electrophilic n-4-diene complexes, 3 will be conducted. Chief questions of interest include the regio- and stereoselectivity of attack on 3 by nucleophiles. Development of synthetically useful methodologies from these studies may have future applicability in the construction of complex natural products.