33 research outputs found
Fritz Haber: The Damned Scientist
In the gallery of famous people tracing their origins to Wroc{\l}aw, few are
as controversial, as complex, or as tragic as Fritz Haber, ever more distant in
the flux of time, yet still stirring emotions. He developed a method for the
direct synthesis of ammonia from its elements and later pioneered chemical
warfare on the battlefields of the First World War.Comment: 17 pages; Dedicated to the Fritz Haber Institute,Berlin, on the
occasion of its 100th anniversary; German version of this article published
in Angew. Chem. 2011, 123, 10226 - 10240; DOI: 10.1002/ange.20110542
ÎČ-Selective One-Pot Synthesis of Acyl-C-Glycosides via CoreyâSeebach Umpolung Reaction
Efficient CopperâCatalyzed Highly Stereoselective Synthesis of Unprotected CâAcyl Mannoâ, Rhamnoâ and Lyxopyranosides
Due to their high stability towards enzymatic hydrolysis C-acyl glycosidic compounds are useful synthetic intermediates for potential candidates in drug discovery. Syntheses for C-acyl mannosides have remained scarce and usually employ donors obtained from lengthy syntheses. Furthermore, syntheses of unprotected C-acyl mannosides have not been reported so far, due to the incapability of the C-acyl mannoside motif with deprotection conditions for protective groups commonly used in carbohydrate chemistry. Herein, we report an efficient and highly alpha-selective four-step one-pot method for the synthesis of C-acyl alpha-d-manno-, l-rhamno- and d-lyxopyranosides from easily accessible persilylated monosaccharides and dithianes requiring only trace amounts of a copper source as catalyst and explain the crucial role of the catalyst by mechanistic studies. Furthermore, the C-acyl alpha-glycosides were easily isomerized to give rapid access to their beta-anomers