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Development of New Synthetic Reactions by Rare Earth Metals

稀土金属新合成反应的进展

基本信息

批准号：
63550651
负责人：
FUJIWARA Yuzo
金额：
$ 1.02万
依托单位：
HIROSHIMA UNIVERSITY (1989)Kyushu University (1988)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

By studies on this project, the following novel synthetic reactions have been found by utilizing samarium(Sm) and ytterbium(Yb) metals.1. Samarium Metal Promoted Selective Synthesis of Azoxy Compounds. We found that Sm metal can reduce various nitroarenes at room temperature to give the corresponding azoxy compounds selectively; a bromine, iodine, or carbonyl group in the substrates is retained. This method, because of its simplicity and high selectivity, constitutes a useful alternative to the commonly accepted procedures for the synthesis of azoxy compounds.2. Ytterbium Metal Mediated Synthesis of Unsymmetrical 1,2-Diols. We found that Yb metal reacts with diaryl ketones such as benzophenone, phenyl methyl ketone and 9-fluorenone to form metallaoxirane intermediates which further react with ketones and aldehydes to give the corresponding cross- coupling products, unsymmetrical 1,2-diols in high yields.Similarly, the metallaoxirane intermediate has been found to undergo nucleophilic addition to various electrophfles such as epoxides, nitriles, esters, CO_2 etc., to give the corresponding cross-coupling products. Because these reactions of Yb-umpoled ketones with electrophiles proceed under very mild conditions to give high yields, and have simplicity of the procedure, the present reactions constitute useful methods for the synthesis of not only unsymmetrical 1,2-diols but also 1,3-diols, alpha-hydroxy ketones, etc.Through this project, rare earth metals, the simplest reagent have been found to act as very useful synthetic reagents under mild conditions.

通过本项目的研究，利用钐（Sm）和镱（Yb）金属发现了以下新的合成反应.钐金属促进的氧化偶氮化合物的选择性合成。我们发现，Sm金属可以在室温下还原各种硝基芳烃，得到相应的氧化偶氮化合物选择性;溴，碘，或羰基在基板上保留。该方法简单、选择性高，是合成氧化偶氮化合物的一种有效方法.金属镱介导的不对称1，2-二醇的合成。我们发现Yb金属与二芳基酮如二苯甲酮、苯甲基酮和9-芴酮反应生成金属环氧乙烷中间体，再与酮和醛反应，高产率地得到相应的交叉偶联产物--不对称1，2-二醇.同样，金属环氧乙烷中间体还与环氧化物、腈、酯、CO_2等亲核加成反应，以给出相应的交叉耦合产物。由于Yb-极化的酮与亲电试剂的这些反应在非常温和的条件下进行，得到高产率，并且具有简单的步骤，因此本反应不仅构成了合成不对称1，2-二醇的有用方法，而且构成了合成1，3-二醇、α-羟基酮等的有用方法。已经发现最简单的试剂在温和条件下作为非常有用的合成试剂。