BORON-ACTIVATED CYCLOADDITIONS AND RELATED REACTIONS

根据最近的发现证明了高反应性， 区域选择性和立体选择性，以及许多独特的特征 在乙烯基硼烷的Diels-Alder反应中，这一提议旨在开发一种 各种硼活化的环加成反应和相关反应。冲向 为此，一个主要目标是开发新的和有用的乙烯基硼烷 以及相关的Diels-Alder双烯亲和者。第二个目标是扩大 展示了与乙烯基硼烷的Diels-Alder反应的范围，包括 高官能化双烯的应用及立体化学研究 分子内反应，以获得足够广泛的基础 了解这些反应，以便规划它们在复杂环境中的使用 综合。 另一个目标是推广最近的一项发现，即少量的 硼烷可催化二烯与未活化的Diels-Alder反应 乙炔。我们催化反应的适度改进可能会 提供工业上可用的工艺。拟议的工作还将继续 实用化不对称反应的发展。 最后，最近发现的第二个硼活化的周环 烯烃的烯丙基硼化反应，暗示着一种巨大而多样的直接反应。 与烯烃反应的用途，以及许多有用的新合成方法 基于烯丙基硼化产物的二次转化。它是 建议广泛研究烯丙基硼的范围，目标是 充分发展这一新的、独特的碳-碳键形成反应。 这份提案中与健康相关的工作源于一位诚实的 对多种药物合成方法的影响 重要的天然和人造物质。

On the basis of recent discoveries demonstrating the high reactivity, regioselectivity, and stereoselectivity, and many unique characteristics of Diels-Alder reactions of vinylboranes, this proposal aims to develop a variety of boron-activated cycloadditions and related reactions. Toward that end, a primary objective is to develop new and useful vinylboranes and related Diels-Alder dienophiles. A second objective is to broaden the demonstrated scope of Diels-Alder reactions with vinylboranes, including the use of highly functionalized dienes and a study of the stereochemistry of intramolecular reactions, in order to gain sufficiently broad-based knowledge of these reactions to allow the planning of their use in complex syntheses. Another goal is to generalize a recent discovery that small amounts of boranes can catalyze Diels-Alder reactions of dienes with unactivated acetylenes. Modest improvements in our catalytic reaction could furnish industrially usable processes. The proposed work will also pursue the development of practical asymmetric reactions. Finally, recent discoveries with a second boron-activated pericyclic reaction, the allylboration of alkenes, suggest a huge and varied direct utility of reactions with alkenes, and many useful new synthetic methods based on secondary conversions of the allylboration products. It is proposed to extensively study the scope of allylborations with the goal of fully developing this new and unique carbon-carbon bond forming reaction. The health-relatedness to the work in this proposal derives from an honest impact on methods for the synthesis of a wide variety of medicinally important natural and artificial substances.