Palladium-Catalyzed Alkene Carboamination: A New Tool for the Synthesis of Iminosugar C-Glycosides

Session: 
PS2 Poster session 2 Even numbers
Code: 
P68
Location (hall): 
Foyer
Start/end time: 
Tuesday, July 2, 2019 - 15:45 to 17:15
Estelle
Gallienne

Salia Tangara1, Sophie Front1, Olivier Martin1Estelle Gallienne1

1ICOA - Universite d'Orleans, Orleans, France

Intramolecular palladium-catalyzed alkene carboamination is a particularly atom-efficient reaction, which allows in a single step the concomitant formation of a C-N bond, a C-C bond and up to two stereocenters from a protected aminoalkene with a high degree of regio- and diastereoselectivity. This reaction involves a combination of an air-stable palladium complex with a commercially available phosphine ligand in the presence of a base and an aryl, alkenyl or alkynyl halide [1]. This intramolecular reaction has mainly been employed for the synthesis of five-membered nitrogen heterocycles, but it has never been used for the synthesis of highly functionalized heterocycles such as iminosugar C-glycosides [2].

Iminosugars are glycomimetics known for inhibiting carbohydrate processing enzymes, in which the endocyclic oxygen is replaced by a nitrogen atom [3]. As anomeric configuration is fundamental to the biological activity of carbohydrates, incorporating this information in the structure of glycomimetics is crucial and makes iminosugar C-glycosides more interesting, as they can exist in the form of two different pseudo anomers, even if their synthesis is much more challenging [4].

This new methodology will allow in a few steps the synthesis of iminosugar libraries with a high degree of molecular diversity, which will be achieved by the use of different commercially available sugars as starting materials (aldoses/ketoses, pentoses/hexoses, furanose/pyranose forms) and by the use of different commercially available aryl, alkenyl or alkynyl halides. Biological evaluation of the synthesized compounds towards a panel of enzymes will be realized.

The synthesis of various sugar-derived aminoalkenes will be presented, as well as the optimization of carboamination reaction conditions leading to a diversity of novel iminosugar C-glycosides in a highly diastereoselective process.

References: 
  1. Wolfe, J. P. Stereoselective synthesis of saturated heterocycles via palladium-catalyzed alkene carboetherification and carboamination reactions, Synlett 2008, 19, 2913-2937.
  2. Wolfe, J. P. Synthesis of saturated heterocycles via metal-catalyzed alkene carboamination or carboalkoxylation reactions, Top. Heterocycl. Chem. 2013, 32, 1-38.
  3. Iminosugars: From Synthesis to Therapeutic Applications; Compain, P., Martin, O. R., Eds.; Wiley-VCH: Weinheim, 2007.
  4. Compain, P.; Chagnault, V.; Martin, O. R. Tactics and strategies for the synthesis of iminosugar C-glycosides: a review, Tetrahedron: Asymmetry 2009, 20, 672-711.

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