IRON COMPLEXES IN ACYCLIC POLYENE SYNTHESIS

白三烯（LT）是脂质代谢物，其充当支气管和支气管平滑肌。 血管收缩剂，并且已知增加血管渗透性。 研究结果表明，抑制剂对体内形成的 白细胞三烯在治疗 支气管哮喘和过敏反应。 由于天然气低 大量的LT，只有合成的可用性 白三烯和白三烯衍生物将允许未来 生物作用和代谢的机制研究 这些重要的生物分子。 白三烯结构提出了两个合成挑战- 顺式-二乙烯基甲烷官能度和立体特异性 引入烯丙基氧官能团。 新合成 将制定方法，通过以下方式应对这两项挑战 利用1）容易的制备、分辨率和 手性（二烯）铁阳离子与亲核试剂的反应性， 得到反，顺-1，3-二烯。 由于共轭三烯部分 已知白三烯结构的一部分 空气氧化，通过络合作用对多烯的“保护”， 铁将是一个巨大的优势， 处理这些敏感化合物。 一个不断增长的新类别的抗生素是多烯大环内酯。 这些化合物的特征是具有共轭多烯链段 (4-7双带）以及相邻的片段， 四个相邻的手性中心 新的合成方法将是 开发用于这些中心的不对称合成， 一种最初的前手性二烯。 这将通过以下方式实现： 与立体化学定向铁（三羰基）络合 附属物。

Leukotrienes (LT's) are lipid metabolites which act as broncho and vasoconstrictors and are known to increase vascular permeability. Findings indicate that inhibitors toward the in vivo formation of leukotrienes could be of therapeutic value in the treatment of bronchial asthma and allergic reactions. Due to the low natural abundance of the LT's, only the availability of synthetic leukotrienes and leukotriene derivatives will permit future mechanistic studies of the biological action and metabolism of these important bio-molecules. The leukotriene structure presents two synthetic challenges--the cis-divinylmethane functionality and the stereospecific introduction of allylic oxygen functionality. New synthetic methodology will be developed to address these two challenges by taking advantage of 1) the facile preparation, resolution, and reactivity of chiral (diene) iron cations with nucleophiles to afford trans,cis-1,3-dienes. Since the conjugated triene portion of the leukotriene structure is known to be extremely susceptible to air oxidation, the "protection" of the polyene by complexation to iron will be a tremendous advantage in the preparation and handling of these sensitive compounds. A growing new class of antibiotics are the polyene macrolides. These compounds are characterized by a conjugated polyene segment (4-7 double bands) as well as adjacent segments containing up to four contiguous chiral centers. New synthetic methodology will be developed for the asymmetric synthesis of these centers utilizing an originally prochiral diene. This will be accomplished through complexation to the stereochemically directing iron(tricarbonyl) adjunct.