imidazole-containing organoboronic acid catalysts is described. This catalytic process with low catalyst loading enables the introduction of a wide variety of acyl functional groups into the equatorial position of cis-vicinal diols in unprotected hexapyranosides with excellent site selectivity. This is the first example that uses a Lewis base-containing boronicacid to enhance the nucleophilicity of
Recognition and Site-Selective Transformation of Monosaccharides by Using Copper(II) Catalysis
作者:I-Hon Chen、Kevin G. M. Kou、Diane N. Le、Colin M. Rathbun、Vy M. Dong
DOI:10.1002/chem.201400133
日期:2014.4.22
We demonstrate copper(II)‐catalyzed acylation and tosylation of monosaccharides. Various carbohydrate derivatives, including glucopyranosides and ribofuranosides, are obtained in high yields and regioselectivities. Using this versatile strategy, the site of acylation can be switched by choice of ligand. Preliminary mechanistic studies support nucleophilic addition of a copper–sugar complex to the acyl