The Transition Metal Catalyzed Homo Diels-Alder Reaction

过渡金属催化降冰片二烯的[2+2+2]和[4+2+2]同Diels-Alder反应导致高度笼化的产物，由非手性前体产生多达9个新的立体中心。手性双膦配体的使用赋予这些反应显著的立体选择性。拟议的研究集中在扩展这种化学功能化的二烯和亲二烯体和其他homoconjugated二烯，包括双环[2.2.2]辛二烯。此外，区域控制的切割反应的笼加合物将开发，提供访问双环目标。马齿苋醛和相关二萜的合成将说明这种方法的有效性。碳-碳键的形成是合成具有生物或药理活性的复杂分子的重要组成部分。某些类别的反应导致在单个合成步骤中形成多个碳-碳键，并且此外，这种“环加成”反应通常是高度选择性的，仅形成产物的许多可能异构体中的一种。有了这个奖项，有机合成计划支持教授约翰K。波士顿大学化学系的斯奈德说。斯奈德教授正在开发和探索使用一种不寻常的环加成反应来合成复杂的多环结构。对这些复杂结构的化学性质的进一步研究导致了有机合成的新的和有效的策略的发展，如植物生长调节剂portulal的合成所示。

The transition metal catalyzed [2+2+2] and [4+2+2] homo Diels-Alder reactions of norbornadiene lead to highly caged products with the creation of as many as nine new stereocenters from achiral precursors. Use of chiral bisphosphine ligands imparts significant stereoselectivity to these reactions. The proposed studies focus on the expansion of this chemistry to functionalized dienes and dienophiles and to other homoconjugated dienes, including bicyclo[2.2.2]octadienes. In addition, regiocontrolled cleavage reactions of the caged adducts will be developed, affording access to bicyclic targets. Synthesis of portulal and related diterpenes will illustrate the effectiveness of this methodology.Formation of carbon-carbon bonds represents an essential component of the synthesis of the complex molecules displaying biological or pharmacological activity. Certain classes of reactions result in the formation of multiple carbon-carbon bonds in a single synthetic step, and in addition, such "cycloaddition" reactions are often highly selective, forming only one of many possible isomers of the product. With this award, the Organic Synthesis Program supports the studies of Professor John K. Snyder, of the Department of Chemistry at Boston University. Professor Snyder is developing and exploring the use of an unusual type of cycloaddition reaction for the synthesis of complex polycyclic structures. Additional investigations of the chemistry of these complex structures lead to the development of novel and efficient strategies for organic synthesis, as illustrated by the synthesis of a plant growth regulator, portulal.