Enantiopure 1,4,5-Trisubstituted 1,2,3-Triazoles from Carbohydrates: Applications of Organoselenium Chemistry
摘要:
A wide range of stable vinyl selenone-modified furanosides has been synthesized for the first time. These 2 pi-partners undergo 1,3-dipolar cycloaddition reactions with a wide range of organic azides to afford enantiopure trisubstituted triazoles. Furanosyl rings opened up during triazole synthesis to generate polyfunctionalized molecules, ready to undergo further transformations. This strategy is one of the most convenient methods for the synthesis of enantiopure 1,4,5-trisubstituted 1,2,3-triazoles where the chiral components are attached to C-4 or C-5 position of triazole ring. These triazoles are formed in a regioselective manner, and several pairs of regioisomeric triazoles have also been synthesized. The approach affords densely functionalized triazoles, which are amenable to further modifications because of the presence of aldehyde and hydroxyl groups. This powerful and practical route adds to the arsenals of chemists and biologists interested in the synthesis and applications of triazoles.
Enantiopure 1,4,5-Trisubstituted 1,2,3-Triazoles from Carbohydrates: Applications of Organoselenium Chemistry
摘要:
A wide range of stable vinyl selenone-modified furanosides has been synthesized for the first time. These 2 pi-partners undergo 1,3-dipolar cycloaddition reactions with a wide range of organic azides to afford enantiopure trisubstituted triazoles. Furanosyl rings opened up during triazole synthesis to generate polyfunctionalized molecules, ready to undergo further transformations. This strategy is one of the most convenient methods for the synthesis of enantiopure 1,4,5-trisubstituted 1,2,3-triazoles where the chiral components are attached to C-4 or C-5 position of triazole ring. These triazoles are formed in a regioselective manner, and several pairs of regioisomeric triazoles have also been synthesized. The approach affords densely functionalized triazoles, which are amenable to further modifications because of the presence of aldehyde and hydroxyl groups. This powerful and practical route adds to the arsenals of chemists and biologists interested in the synthesis and applications of triazoles.
Unusual addition of amines to C-2 of vinyl sulfone-modified-β-d-pent-2-enofuranosyl carbohydrates: synthesis of a new class of β-anomeric 2-amino-2,3-dideoxy-d-threo-pentofuranosides
作者:Indrajit Das、Cheravakkattu G. Suresh、Jean-Luc Décout、Tanmaya Pathak
DOI:10.1016/j.carres.2008.03.022
日期:2008.6
When 3-C-sulfonyl-pent-2-enofuranosides and 3-C-sulfonyl-hex-2-enofuranosides were reacted with primary and secondary amines, only the beta-anomeric methoxy group of the pent-2-enofuranoside did not cause any hindrance to incoming nitrogen nucleophiles. This resulted in the 'unusual' addition of amines, in which the diastereoselectivity of the reaction was overwhelmingly in favor of amino sugars of the D-arabino configuration. Selected products were desulfonylated to obtain a new class of beta-anomeric 2-amino-2,3-dideoxy-D-threo-pentofuranosides. (C) 2008 Elsevier Ltd. All rights reserved.