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Selective formation of beta-O-aryl glycosides in the absence of the C(2)-ester neighboring group.
J Org Chem. 2009 Jul 03; 74(13):4705-11.JO

Abstract

The development of a general and practical method for the stereoselective synthesis of beta-O-aryl glycosides that exploits the nature of a cationic palladium(II) catalyst, instead of a C(2)-ester directing group, to control the beta-selectivity is described. This beta-glycosylation reaction is highly diastereoselective and requires 2-3 mol % of Pd(CH(3)CN)(4)(BF(4))(2) to activate glycosyl trichloroacetimidate donors at room temperature. The current method has been applied to d-glucose, d-galactose, and d-xylose donors with a nondirecting group incorporated at the C(2)-position to provide the O-aryl glycosides with good to excellent beta-selectivity. In addition, its application is widespread to electron-donating, electron-withdrawing, and hindered phenols. The reaction is likely to proceed through a seven-membered ring intermediate, wherein the palladium catalyst coordinates to both C(1)-trichloroacetimidate nitrogen and C(2)-oxygen of the donor, blocking the alpha-face. As a result, the phenol nucleophile preferentially approaches to the top face of the activated donor, leading to formation of the beta-O-aryl glycoside.

Authors+Show Affiliations

Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

19485363

Citation

McKay, Matthew J., et al. "Selective Formation of beta-O-aryl Glycosides in the Absence of the C(2)-ester Neighboring Group." The Journal of Organic Chemistry, vol. 74, no. 13, 2009, pp. 4705-11.
McKay MJ, Naab BD, Mercer GJ, et al. Selective formation of beta-O-aryl glycosides in the absence of the C(2)-ester neighboring group. J Org Chem. 2009;74(13):4705-11.
McKay, M. J., Naab, B. D., Mercer, G. J., & Nguyen, H. M. (2009). Selective formation of beta-O-aryl glycosides in the absence of the C(2)-ester neighboring group. The Journal of Organic Chemistry, 74(13), 4705-11. https://doi.org/10.1021/jo9002807
McKay MJ, et al. Selective Formation of beta-O-aryl Glycosides in the Absence of the C(2)-ester Neighboring Group. J Org Chem. 2009 Jul 3;74(13):4705-11. PubMed PMID: 19485363.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Selective formation of beta-O-aryl glycosides in the absence of the C(2)-ester neighboring group. AU - McKay,Matthew J, AU - Naab,Benjamin D, AU - Mercer,Gregory J, AU - Nguyen,Hien M, PY - 2009/6/3/entrez PY - 2009/6/3/pubmed PY - 2009/11/7/medline SP - 4705 EP - 11 JF - The Journal of organic chemistry JO - J. Org. Chem. VL - 74 IS - 13 N2 - The development of a general and practical method for the stereoselective synthesis of beta-O-aryl glycosides that exploits the nature of a cationic palladium(II) catalyst, instead of a C(2)-ester directing group, to control the beta-selectivity is described. This beta-glycosylation reaction is highly diastereoselective and requires 2-3 mol % of Pd(CH(3)CN)(4)(BF(4))(2) to activate glycosyl trichloroacetimidate donors at room temperature. The current method has been applied to d-glucose, d-galactose, and d-xylose donors with a nondirecting group incorporated at the C(2)-position to provide the O-aryl glycosides with good to excellent beta-selectivity. In addition, its application is widespread to electron-donating, electron-withdrawing, and hindered phenols. The reaction is likely to proceed through a seven-membered ring intermediate, wherein the palladium catalyst coordinates to both C(1)-trichloroacetimidate nitrogen and C(2)-oxygen of the donor, blocking the alpha-face. As a result, the phenol nucleophile preferentially approaches to the top face of the activated donor, leading to formation of the beta-O-aryl glycoside. SN - 1520-6904 UR - https://www.unboundmedicine.com/medline/citation/19485363/Selective_formation_of_beta_O_aryl_glycosides_in_the_absence_of_the_C_2__ester_neighboring_group_ L2 - https://dx.doi.org/10.1021/jo9002807 DB - PRIME DP - Unbound Medicine ER -