Asymmetric Synthesis with Chiral Heteroalkyl Radicals

在有机和大分子化学计划的支持下，凯斯西储大学化学系的Philip P. Garner教授正在研究使用手性杂烷基的不对称合成。Garner教授正在开发一种通用的、迭代的聚合物支持的多元醇自由基合成方法，并将吡喃糖苷手性助剂的使用扩展到合成有用的闭壳过程。这种迭代方法的最佳树脂连接策略将被定义和技术开发的聚合物支持的反应的定量。还将探索减少自由基同系化序列的每次迭代所需的步骤数和削减手性助剂的结构的方法。吡喃糖苷类手性助剂将被应用于各种有用的闭壳过程。协调的环加成，烯丙基硼/烯醇化物烷基化，和串联的不对称硼氢化/铃木耦合序列将被检查，在溶液中和聚合物supports.While有机反应传统上进行的溶液中，允许密切混合的反应物，有许多优点，找到反应物或试剂连接到一个不溶性的“支持”的反应。“例如，如果用过的试剂附着在这种载体上，它可以很容易地从反应混合物中除去，而如果附着了所需的化合物，杂质可以很容易地洗掉。凯斯西储大学化学系的Philip P. Garner教授因其在该领域的努力而得到了有机和高分子化学项目的支持。加纳教授正在利用含有未成对电子（“自由基”）的化合物的反应化学，寻找控制其反应性的方法，以便对其反应产物进行精确的几何控制。

With the support of the Organic and Macromolecular Chemistry Program, Professor Philip P. Garner, of the Department of Chemistry at Case Western Reserve University, is studying asymmetric synthesis using chiral heteroalkyl radicals. Professor Garner is both developing a general, iterative polymer-supported radical synthesis of polyols and extending the use of pyranosidic chiral auxiliaries to synthetically useful closed-shell processes. The optimal resin-linker strategy for this iterative approach will be defined and techniques developed for the quantification of polymer-supported reactions. Methods for reducing the number of steps required for each iteration of the radical homologation sequence and paring down the structure of the chiral auxiliary will also be explored. Pyranosidic chiral auxiliaries will be applied to a variety of useful closed-shell processes. Concerted cycloadditions, allylboron/enolate alkylations, and a tandem asymmetric hydroboration/Suzuki coupling sequence will be examined, both in solution and on polymer supports.While organic reactions have traditionally been carried out in solution, allowing intimate mixing of reactants, there are many advantages to finding reactions in which either a reactant or a reagent is linked to an insoluble "support." If a spent reagent is attached to such a support, for example, it may be easily removed from the reaction mixture, while if a desired compound is attached, impurities may be easily washed away. Professor Philip P. Garner, of the Department of Chemistry at Case Western Reserve University, is supported by the Organic and Macromolecular Chemistry Program for his efforts in this area. Professor Garner is harnessing the reaction chemistry of compounds containing an unpaired electron ("radicals"), finding ways to control their reactivity so as to allow precise geometrical control over the products of their reactions.