Asymmetric Synthesis with Chiral Heteroalkyl Radicals

有机合成计划支持教授菲利普P加纳， 凯斯西储大学化学系， 一类新的可回收手性化合物的开发研究 用于手性杂烷基不对称合成的助剂。 原型羟烷基自由基等同物含有手性缩醛基团 来源于碳水化合物或萜烯。 一般方法， 包括自由基移位，用于形成手性 乙醛氧基烷基自由基正在开发中，用于制备 这些材料。 辅助结构的系统变化， 再加上从头算过渡态结构建模，解决了 负责不对称诱导的相互作用的性质， 有利于其优化。 分子间和分子内变体 原子/基团转移反应以及碳-碳加成 双键进行了探讨，因为这是方法，以允许有效的 手性助剂的去除和再利用。 双向迭代 不对称的“自由基羟醛缩合”反应的形式有望立体控制 获得1，3-多元醇。 与通常定义明确的化合物化学相反， 偶数个电子，含有未成对电子的化合物 （自由基）往往是如此活泼，他们的反应化学是 难以驾驭。 缺乏反应控制是一个特别的问题 在通过化合物的自由基的尝试合成中， 手性的性质，其中一个分子与另一个分子在手性上不同， 就像右手和左手不同一样。 的支持下 有机合成程序，教授菲利普P.加纳，该部门 凯斯西储大学的化学教授，正在开发化学 这些方法允许利用 自由基，同时保持对手性的高水平控制， 所产生的产品。 这些方法提供了新的途径， 生物活性化合物的合成，这些化合物通常是手性的。

The Organic Synthesis Program supports Professor Philip P. Garner, of the Department of Chemistry of Case Western Reserve University, in his studies of the development of a new class of recyclable chiral auxiliaries for asymmetric synthesis with chiral heteroalkyl radicals. Prototype hydroxyalkyl radical equivalents contain a chiral acetal group derived from either carbohydrates or terpenes. General methods, including radical translocation, for the formation of chiral acetaloxyalkyl radicals are under development for the preparation of these materials. Systematic variation of the auxiliary structure, coupled with ab initio transition state structure modeling, addresses the nature of the interactions responsible for asymmetric induction and facilitates their optimization. Both inter- and intramolecular variants of atom/group transfer reactions as well as additions to carbon-carbon double bonds are explored, as is methodology to permit the efficient removal and reuse of the chiral auxiliaries. Bidirectional and iterative versions of asymmetric `radical aldol` reactions promise stereocontrolled access to 1,3-polyols. In contrast to the often well-defined chemistry of compounds containing even numbers of electrons, compounds containing an unpaired electron (radicals) are often so reactive that their reaction chemistry is difficult to harness. Lack of reaction control is a particular problem in the attempted synthesis via radicals of compounds displaying the property of chirality, wherein a molecule differs from another in the same way a right hand differs from a left. With the support of the Organic Synthesis Program, Professor Philip P. Garner, of the Department of Chemistry of Case Western Reserve University, is developing chemical approaches which allow the exploitation of the intrinsic reactivity of radicals while maintaining a high level of control over the chirality of the resulting products. These approaches offer new routes for the synthesis of biologically active compounds, which are often chiral.