2595-18-8Relevant academic research and scientific papers
Selective Catalytic Oxidation of Unprotected Carbohydrates
Chung, Kevin,Waymouth, Robert M.
, p. 4653 - 4659 (2016/07/12)
The development of new strategies for the direct catalytic functionalization of unprotected carbohydrates would be an enabling advance for glycoscience. Herein we report that the catalytic oxidation of unprotected carbohydrates can be carried out selectively with [(neocuproine)Pd(OAc)]2(OTf)2 (1) to generate the 3-ketoses. Catalytic aerobic oxidation can be carried out with Pd loadings as low as 1% in the presence of phenolic additives. Catalytic oxidation of a variety of unprotected pyranosides in acetonitrile or acetonitrile/water with Pd catalyst 1 with either oxygen or benzoquinone selectively generates the 3-ketoses. Minor amounts of the 4-ketoses are formed competitively, particularly in the case of pyranosides bearing axial substituents at C4 of the pyranoside. Catalytic oxidations can also be carried out in trifluorethanol, but for pyranosides bearing axial substituents at C2 or C4, selective oxidation to the 3-ketose is accompanied by epimerization to afford the equatorial 3-ketoses. Catalytic oxidation of unprotected hexafuranosides or sialic acid derivatives occurs selectively at the exocyclic diol or triol in trifluoroethanol to generate exocyclic hydroxyketones.
Catalytic and regioselective oxidation of carbohydrates to synthesize keto-sugars under mild conditions
Muramatsu, Wataru
supporting information, p. 4846 - 4849 (2015/04/27)
A new catalytic and regioselective approach for the synthesis of keto-sugars is described. An organotin catalyst, Oc2SnCl2, in the presence of trimethylphenylammonium tribromide ([TMPhA]+Br3-) accelerates the regioselective oxidation at the axial -OH group of 1,2-diol moieties in galactopyranosides. The reaction conditions can also be used for the regioselective oxidation of various carbohydrates.
