‘Click’ Preparation of Carbohydrate 1-Benzotriazoles, 1,4-Disubstituted, and 1,4,5-Trisubstituted Triazoles and their Utility as Glycosyl Donors*

Jacinta A. Watt; Carlie T. Gannon; Karen J. Loft; Zoran Dinev; Spencer J. Williams

doi:10.1071/CH08364

RESEARCH ARTICLE

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‘Click’ Preparation of Carbohydrate 1-Benzotriazoles, 1,4-Disubstituted, and 1,4,5-Trisubstituted Triazoles and their Utility as Glycosyl Donors*

Jacinta A. Watt ^A , Carlie T. Gannon ^A , Karen J. Loft ^A , Zoran Dinev ^A and Spencer J. Williams ^A ^B

+ Author Affiliations

- Author Affiliations

^A School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic. 3010, Australia.

^B Corresponding author. Email: sjwill@unimelb.edu.au

Australian Journal of Chemistry 61(11) 837-846 https://doi.org/10.1071/CH08364
Submitted: 29 August 2008 Accepted: 12 September 2008 Published: 5 November 2008

Abstract

Glycosyl triazoles can be prepared from readily available anomeric azides through various ‘click’ methodologies: thermal Huisgen cycloaddition with alkynes, strain-promoted Huisgen cycloaddition of benzynes, and Cu^I-catalyzed azide-alkyne cycloaddition of terminal alkynes (CuAAC reaction). Here we investigate the formation of glycosyl 1-benzotriazoles from anomeric and non-anomeric carbohydrate azides using benzynes derived from substituted anthranilic acids. The reactivity of the resulting anomeric 1-benzotriazoles as glycosyl donors was investigated and compared with 1,4-disubstituted glycosyl triazoles (from the CuAAC reaction) and 1,4,5-trisubstituted glycosyl triazoles (prepared by Huisgen cycloaddition of glycosyl azides and dimethyl acetylene dicarboxylate). The 1,4,5-trisubstituted glycosyl triazoles were activated by Lewis acids and could be converted to O-glycosides, S-glycosides, glycosyl chlorides, and glycosyl azides. By contrast, under all conditions investigated, the 1,4-disubstituted glycosyl triazoles were unreactive as glycosyl donors. Glycosyl 1-benzotriazoles were generally inert as glycosyl donors; however, a tetrafluorobenzotriazole derivative, which bears electron-withdrawing substituents on the benzotriazole group, was a moderate glycosyl donor and could be converted to an S-glycoside by treatment with thiocresol and tin(iv) chloride.

^* The present paper is dedicated to Professor Bob Stick to mark the occasion of his retirement and 65th birthday.

Acknowledgements

The Australian Research Council is thanked for financial support. J.A.W. and K.J.L. were partially supported by the University of Melbourne. High resolution mass spectrometry (HRMS) was performed by Messrs Hadi Loie, Chris Barlow, and Adrian Lam.

References

‘Click’ Preparation of Carbohydrate 1-Benzotriazoles, 1,4-Disubstituted, and 1,4,5-Trisubstituted Triazoles and their Utility as Glycosyl Donors*

Abstract

Acknowledgements

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