Application of the Indium-Mediated Allylation Reaction: Synthesis of 3-Deoxy-2-Uloses

Session: 
PS2 Poster session 2 Even numbers
Code: 
P70
Location (hall): 
Foyer
Start/end time: 
Tuesday, July 2, 2019 - 15:45 to 17:15
Manuel
Gintner

Manuel Gintner1, Christian Denner1, Christoph Schmölzer1, Michael Fischer1, Peter Frühauf2, Hanspeter Kählig1, Walther Schmid1

1Institute of Organic Chemsitry, University Of Vienna, Vienna, Austria, 2Institute of Analytical Chemistry, University of Vienna, Vienna, Austria

The indium-mediated allylation reaction is a powerful tool for the elongation of carbohydrates since it can be performed in aqueous media under mild conditions [1,2]. We utilized this reaction in the synthesis of carbohydrate scaffolds containing the 3-deoxy-2-ulose motif, a barely investigated compound class [3]. The stereoselective outcome can be controlled by the presence or absence of a chelating group in α-position to the reacting carbonyl function as we verify on two model substrates [4,5]. Our approach towards the synthesis of 3-deoxy-D glycero-D-galacto-2-nonulose - the ketose analogue of widely distributed 2-keto-3-deoxy-D-glycero-D-galacto-nonoic acid (KDN) - is accompanied by demanding epimer separation which has been tackled by the introduction of an UV-active group attached to the allyl building block facilitating detection using HPLC. Synthetic as well as experimental details will be presented.

Scheme: Application of the indium-mediated allylation reaction in the synthesis of 3-deoxy-2-uloses and tackling of demanding epimer separation.

References: 
  1. Bowyer, W. J.; Singaram, B.; Sessler, A. M. Nature of the intermediates formed during indium mediated allylation under Barbier conditions. Spectroscopic and experimental data on allylindium species. Tetrahedron 2011, 67, 7449.
  2. Podlech, J.; Maier, T. C. Indium in Organic Synthesis. Synthesis 2003, 5, 633.
  3. Schmölzer, C.; Fischer, M.; Schmid, W. Permanganate Oxidation Revisited: Synthesis of 3 Deoxy-2-uloses via Indium-Mediated Chain Elongation of Carbohydrates. Eur. J. Org. Chem. 2010, 25, 4886.
  4. Li, C. J., Chan, T. H. Organic Syntheses Using Indium-Mediated and Catalyzed Reactions in Aqueous Media. Tetrahedron 1999, 55, 11149.
  5. Paquette, L. A. Evaluation of Chelation Effects Operative during Diastereoselective Addition of the Allylindium Reagent to 2- and 3-Hydroxycyclohexanones in Aqueous, Organic, and Mixed Solvent Systems. Synthesis 2003, 5, 765.

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