|Budget Amount *help
¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1989 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1988 : ¥1,200,000 (Direct Cost : ¥1,200,000)
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.