TY - JOUR
T1 - Application of silver N-heterocyclic carbene complexes in O-glycosidation reactions
AU - Talisman, Ian J.
AU - Kumar, Vineet
AU - Deschamps, Jeffrey R.
AU - Frisch, Mark
AU - Malhotra, Sanjay V.
N1 - Funding Information:
This project has been funded in whole or in part with federal funds from the NCI , National Institutes of Health , under Contract No. HSN261200800001E. X-ray studies were supported by NIDA under interagency agreement Y1-DA1101. The authors would like to thank Dr. Que N. Van for the HBMC of compound 3l .
PY - 2011/11/8
Y1 - 2011/11/8
N2 - We report the efficient O-glycosidation of glycosyl bromides with therapeutically relevant acceptors facilitated by silver N-heterocyclic carbene (Ag-NHC) complexes. A set of four Ag-NHC complexes was synthesized and evaluated as promoters for glycosidation reactions. Two new bis-Ag-NHC complexes derived from ionic liquids 1-benzyl-3-methyl-1H-imidazolium chloride and 1-(2-methoxyethyl)-3-methylimidazolium chloride were found to efficiently promote glycosidation, whereas known mono-Ag complexes of 1,3-bis(2,4,6- trimethylphenyl)imidazolium chloride and 1,3-bis(2,6-di-isopropylphenyl) imidazolium chloride failed to facilitate the reaction. The structures of the promoters were established by X-ray crystallography and these complexes were employed in the glycosidation of different glycosyl bromide donors with biologically valuable acceptors, such as estrone, estradiol, and various flavones. The products were obtained in yields considered good to excellent, and all reactions were highly selective for the β isomer regardless of neighboring group effects.
AB - We report the efficient O-glycosidation of glycosyl bromides with therapeutically relevant acceptors facilitated by silver N-heterocyclic carbene (Ag-NHC) complexes. A set of four Ag-NHC complexes was synthesized and evaluated as promoters for glycosidation reactions. Two new bis-Ag-NHC complexes derived from ionic liquids 1-benzyl-3-methyl-1H-imidazolium chloride and 1-(2-methoxyethyl)-3-methylimidazolium chloride were found to efficiently promote glycosidation, whereas known mono-Ag complexes of 1,3-bis(2,4,6- trimethylphenyl)imidazolium chloride and 1,3-bis(2,6-di-isopropylphenyl) imidazolium chloride failed to facilitate the reaction. The structures of the promoters were established by X-ray crystallography and these complexes were employed in the glycosidation of different glycosyl bromide donors with biologically valuable acceptors, such as estrone, estradiol, and various flavones. The products were obtained in yields considered good to excellent, and all reactions were highly selective for the β isomer regardless of neighboring group effects.
KW - Carbohydrates
KW - O-Glycosidation
KW - Silver N-heterocyclic carbene complex
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U2 - 10.1016/j.carres.2011.07.025
DO - 10.1016/j.carres.2011.07.025
M3 - Article
C2 - 21911215
AN - SCOPUS:80053935577
SN - 0008-6215
VL - 346
SP - 2337
EP - 2341
JO - Carbohydrate Research
JF - Carbohydrate Research
IS - 15
ER -