Cation Radicals in Solution

这项研究由合成有机化学项目资助，由德克萨斯大学奥斯汀分校化学系的内森·L·鲍尔德博士进行研究。这项工作将开发新的温和反应，以形成复杂的环结构。在农业和医药中使用的许多物质中都有这些结构。这项研究继续发展空穴催化的周环反应，无论是为了合成目的，还是为了从根本上了解有机阳离子自由基的结构和反应路径。空穴催化的Diels-Alder反应(DA)已经得到了广泛的发展，最近在倍半萜天然产物(-)-B-Selinene的合成中得到了应用。计划对这一反应和其他周环反应进行进一步的机理、立体化学和动力学研究，以便更果断地回答与反应一致性、角色选择性以及直接和间接有关的基本问题。一种新的和强大的方法，在净DA意义上间接加成高度受阻的二烯烃已经开发出来，并将改进，推广，并说明在合成的化合物在二甲胺系列。以前的空穴催化的直接Diels-Alder应用(例如B-硒)强调了二烯/富含电子的烯烃格式。已经观察到并将开发一种新的、非常有前途的策略，用于在二烯/二烯形式中实现Diels-Alder环加成反应，但它仍能产生高度不同的烯烃官能团。新开发的空穴催化的乙烯基环丁烷重排反应可用于实现净Diels-Alder加成。空穴催化的乙烯基环丁烷反应也将在机理和合成意义上得到广泛发展。

This research is being funded by the Synthetic Organic Chemistry Program for the research of Dr. Nathan L. Bauld of the Department of Chemistry at the University of Texas at Austin. The work will develop new mild reactions for forming complex ring structures. These structures are found in many of the substances used in agriculture and medicine. The research continues the development of hole-catalyzed pericyclic reactions, both for synthetic purposes and to gain fundamental understanding of the structures and reaction paths of organic cation radicals. The hole-catalyzed Diels-Alder reaction (DA) has undergone extensive development and has recently been exemplified in the synthesis of the sesquiterpene natural product (-)-B-selinene. Further mechanistic, stereochemical, and kinetic studies of this and other pericyclic reactions are planned in order to answer more decisively fundamental questions relating to reaction concert, role selectivity, and directness vs. indirectness. A new and powerful methodology for indirect addition in a net DA sense to highly hindered dienes has been developed and will be refined, extended, and illustrated in the synthesis of compounds in the drimane series. Previous hole-catalyzed direct Diels-Alder applications (e.g. B-selinene) have emphasized the diene/electron rich alkene format. A new and very promising strategy for effecting Diels-Alder cycloadditions in the diene/diene format, which nevertheless produces highly differentiated alkene functionalities, has been observed and will be developed. The newly developed hole-catalyzed vinylcyclobutane rearrangement can be used to achieve net Diels-Alder addition. The hole-catalyzed vinylcyclobutane reaction will also be developed extensively in both a mechanistic and synthetic sense.