Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Feb 3;7(2):1438-1445.
doi: 10.1021/acscatal.6b03459. Epub 2017 Jan 18.

Regioselective Carbohydrate Oxidations: A Nuclear Magnetic Resonance (NMR) Study on Selectivity, Rate, and Side-Product Formation

Niek N H M Eisink  1 , Martin D Witte  1 , Adriaan J Minnaard  1
Affiliations

Regioselective Carbohydrate Oxidations: A Nuclear Magnetic Resonance (NMR) Study on Selectivity, Rate, and Side-Product Formation

Niek N H M Eisink et al. ACS Catal. .

Abstract

Palladium/neocuproine catalyzed oxidation of glucosides shows an excellent selectivity for the C3-OH, but in mannosides and galactosides, unselective oxidation was initially observed. For further application in more-complex (oligo)saccharides, a better understanding of the reaction, in terms of selectivity and reactivity, is required. Therefore, a panel of different glycosides was synthesized, subjected to palladium/neocuproine catalyzed oxidation and subsequently analyzed by qNMR. Surprisingly, all studied glucosides, mannosides, galactosides, and xylosides show selective oxidation of the C3-OH. However, subsequent reaction of the resulting ketone moiety is the main culprit for side product formation. Measures are reported to suppress these side reactions. The observed differences in reaction rate, glucosides being the most rapidly oxidized, may be exploited for the selective oxidation of complex oligosaccharides.

Keywords: glycosides; oxidation; palladium; qNMR; regioselective.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Overview of various common glycopyranoses.
Figure 2
Figure 2
Regio and chemoselective oxidation of the terminal glucoside residue in azido-β-d-ketomaltoheptaoside.
Figure 3
Figure 3
Batchwise oxidation of C4-deoxy (7): 1 h = 1 equiv of benzoquinone, 24 h = 3 equiv of benzoquinone.
Scheme 1
Scheme 1. Mechanism of the Rearrangement Taking Place in the Oxidation of Methyl 4-Deoxyglucopyranoside (7)
See this image and copyright information in PMC

References

    1. Dwek R. A. Chem. Rev. 1996, 96, 683–720. 10.1021/cr940283b. - DOI - PubMed
    1. Matsuzaki Y.; Ito Y.; Nakahara Y.; Ogawa T. Tetrahedron Lett. 1993, 34, 1061–1064. 10.1016/S0040-4039(00)77492-2. - DOI
    1. Nicolaou K. C.; Hummel C. W.; Bockovich N. J.; Wong C.-H. J. Chem. Soc., Chem. Commun. 1991, 84, 870–872. 10.1039/c39910000870. - DOI
    1. Toshima K.Synthesis of Carbohydrate Containing Complex Natural Compounds. In The Organic Chemistry of Sugars; Levy D. E., Fügedi P., Eds.; CRC Press: Boca Raton, FL, 2006; pp 576–624.
    1. Jäger M.; Minnaard A. J. Chem. Commun. 2016, 52, 656–664. 10.1039/C5CC08199H. - DOI - PubMed