Functional group transformations in carbohydrates currently often rely on the use of protecting groups and the direct modification of unprotected carbohydrates remains a formidable challenge. [1] In our group an protocol has been developed that regioselectively oxidizes the C-3 hydroxyl group in a broad range of saccharides, including oligosaccharides, to a ketone by a palladium catalyst. [2] This ketone functionality is a versatile handle for further modification, although modification of keto-saccharides, without protecting groups is still under-investigated.
In this project, methyl 3-keto-D-glucose was taken as a model substrate and a plethora of reactions was studied for their compatibility with hydroxyl groups and polar solvents, such as water. The successful transformations resulted for example in synthesis of branched-chain sugars, which are rare motifs found in bacterial sugars. Furthermore, labels and reactive groups could be introduced into the keto-saccharide in one step, that are useful in the field of chemical biology.
- Jäger, M.; Minnaard, A. J. Chem. Commun. 2016, 52, 656–664.
- (a) Jäger, M.; Hartmann, M.; Vries, J. G. De; Minnaard, A. J. Angew. Chem. Int. Ed. 2013, 52, 7809–7812. (b) Chung, K.; Waymouth, R. M. ACS Catal. 2016, 6, 4653–4659. (c) Eisink, N. N. H. M.; Witte, M. D.; Minnaard, A. J. ACS Catal. 2017, 7, 1438–1445.