Alves, M. José

Duarte, Vera C. M.

Fortes, A. Gil

Universidade do Minho: RepositoriUM

 ENANTIOSELECTIVE DIELS-ALDER METHODOLOGY IN THE SYNTHESIS OF AZASUGARS  Duarte V. C. M., Gil Fortes A., Alves M. J.   Centro de Química, Universidade do Minho, Campus de Gualtar 4710-057 Braga, Portugal E-mail: vera10@sapo.pt  Abstract Imino sugars, also known azasugars, are a group of compounds that have received a lot of attention in recent years because they typically exhibit excellent inhibitory properties over a range of enzymes involved in carbohydrate handling and carbohydrate recognizing receptors, widely found in living organisms.1 In our previous work we have been able to obtain optically pure precursor of some important azasugars, like 1-azafagomine and 1-azalactofagomine, by a diastereoselective Diels-Alder strategy using the appropriate 1-glucosyl 1,3-butadiene and 4-phenyl-1,2,4-triazole-3,5-dione (PTAD).2 However, the overall yield obtained in this process was low. In an attempt to overcome this problem, we planned an enantioselective synthesis of precursor 1 as depicted in Scheme 1.  The combination of 2,4-pentadienol and PTAD in the presence of a titanium bound to a TADDOL ligand type3 afforded the best results. The concentration and solvent effect were examined and the results of enantioselectivity obtained will be presented.  References   [1]  Alves, M. J., Azoia, N. G. (2008) In Stereochemistry Research Trends, Nova Science Publishers.  [2] Duarte, V. C. M.; Gil Fortes, A.; Alves, M. J. (2010) communication presented at 46th RICT: Interfacing Chemical Biology and Drug Discovery, Reims – França. [3] Bienaymé, H. (1997) Enantioselective Diels-Alder Cycloaddition by Preorganization on a Chiral Lewis Acid Template Angew. Chem. Int. Ed. Engl., 36, 2670-2673.  Acknowledgements We thank FCT for project funding PTDC/QUI/67407/2006; FCT and FEDER for funding NMR spectrometer Bruker Avance III 400 as part of the National NMR Network RNRMN; V.C.M.D. also thanks for PhD grant (SFRH/BD/61290/2009).  

Enantioselective Diels-Alder methodology in the synthesis of azasugars

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Enantioselective Diels-Alder methodology in the synthesis of azasugars

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Universidade do Minho: RepositoriUM