Abstract
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 ...
Abstract
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.
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