Synthesis of new enantiopure poly(hydroxy)aminooxepanes as building blocks for multivalent carbohydrate mimetics
نویسندگان
چکیده
New compounds with carbohydrate-similar structure (carbohydrate mimetics) are presented in this article. Starting from enantiopure nitrones and lithiated TMSE-allene we prepared three 1,2-oxazine derivatives which underwent a highly stereoselective Lewis acid-induced rearrangement to give bicyclic products in good yield. Subsequent reductive transformations delivered a library of new poly(hydroxy)aminooxepane derivatives. The crucial final palladium-catalyzed hydrogenolysis of the 1,2-oxazine moiety was optimized resulting in a reasonably efficient approach to a series of new seven-membered carbohydrate mimetics.
منابع مشابه
Orthogonally protected sugar diamino acids as building blocks for linear and branched oligosaccharide mimetics.
Sugar amino acids (SAAs), which are carbohydrate derivatives with both an amino group and a carboxyl group connected to the carbohydrate frame, have found wide application as building blocks for oligosaccharide and peptide mimetics, as secondary-structure inducing elements, and as pharmacophore-presenting scaffolds for the generation of combinatorial libraries. Used as monomers with a rigid pyr...
متن کاملSynthesis of multivalent carbohydrate mimetics with aminopolyol end groups and their evaluation as L-selectin inhibitors
In this article a series of divalent and trivalent carbohydrate mimetics on the basis of an enantiopure aminopyran and of serinol is described. These aminopolyols are connected by amide bonds to carboxylic acid derived spacer units either by Schotten-Baumann acylation or by coupling employing HATU as reagent. The O-sulfation employing the SO3·DMF complex was optimized. It was crucial to follow ...
متن کاملFunctionalization of oligosaccharide mimetics and multimerization using squaric diester-mediated coupling.
Functionalized carbohydrate-centered glycoclusters formed the starting material for the synthesis of tagged oligosaccharide and glycoconjugate mimetics, which were obtained by thiourea-bridging, peptide coupling and in particular squaric diester-mediated coupling. The latter method could also be utilized to provide new multivalent glycoconjugates, which were tested for their anti-adhesive prope...
متن کاملAddition of lithiated enol ethers to nitrones and subsequent Lewis acid induced cyclizations to enantiopure 3,6-dihydro-2H-pyrans – an approach to carbohydrate mimetics
A stereodivergent synthesis of enantiopure 3,6-dihydro-2H-pyrans is presented. The addition of lithiated enol ethers to carbohydrate-derived nitrones afforded syn- or anti-configured hydroxylamine derivatives 4a-d that were cyclized under Lewis acidic conditions to yield functionalized dihydropyrans cis- or trans-5a-d containing an enol ether moiety. This functional group was employed for a var...
متن کاملSynthesis of densely functionalized enantiopure indolizidines by ring-closing metathesis (RCM) of hydroxylamines from carbohydrate-derived nitrones
BACKGROUND Indolizidine alkaloids widely occur in nature and display interesting biological activity. This is the reason for which their total synthesis as well as the synthesis of non-natural analogues still attracts the attention of many research groups. To establish new straightforward accesses to these molecules is therefore highly desirable. RESULTS The ring closing metathesis (RCM) of e...
متن کامل