CATALYTIC REDUCTIVE CYCLIZATION

催化还原环化

• 批准号: 2392247
• 负责人: WILLIAM E CROWE
• 金额: $ 14.24万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-01 至 1999-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2392247
• 关键词: catalyst; cyclization; heavy metals; method development; reduction; stereochemistry; titanium; zirconium

The objective of this proposal is to develop the transition metal- mediated reductive coupling of two unsaturated centers into a general, catalytic, stereoselective method for formation of carbon-carbon bonds within carbocyclic and heterocyclic organic target molecules. A notable advantage of the transition metal-catalyzed reductive coupling reaction is that enantioselective transformations can be effected with an inexpensive, achiral stoichiometric reductant in the presence of a substoichiometric quantity of a chiral transition metal complex (asymmetric catalysis). Such a process will be a valuable alternative to reductive coupling protocols which employ an expensive reducing agent in stoichiometric quantities. We propose to study the chemistry of the titanium oxometallacycles and related species formed by reductive cyclization (e.g., azametallacycles, zirconium metallacycles) with the goal of developing useful synthetic protocols for the stereocontrolled synthesis of highly functionalized carbocyclic and heterocyclic compounds. In particular, we will develop new catalytic methods for reductive cyclization.

该提案的目标是开发过渡金属- 介导的两个不饱和中心的还原偶联成为一般的， 用于形成碳-碳键的催化的立体选择性方法 在碳环和杂环有机靶分子中。 一个显著 过渡金属催化还原偶联反应的优点 对映选择性转化可以用 廉价的非手性化学计量还原剂， 亚化学计量量手性过渡金属络合物 （不对称催化）。这一进程将是一个有价值的替代办法， 还原偶联方案使用昂贵的还原剂， 化学计量的量。 我们建议研究钛氧杂环的化学性质， 通过还原环化形成的相关物质（例如，氮杂金属环， 锆金属杂环），目标是开发有用的合成 用于高度官能化的立体控制合成的方案 碳环和杂环化合物。特别是，我们将开发 还原环化反应的新催化方法。