Synthesis of Fullerene Glycoconjugates via a Copper-Catalyzed Huisgen Cycloaddition Reaction
摘要:
The synthesis of fullerene-carbohydrate conjugates using a copper-catalyzed [3 + 2] cycloaddition reaction to facilitate the union of an azido-functionalized sugar and a pentaalkynyl[60]fullerene is straightforward, Thus, fullerenes bearing five oligosaccharides such as Gb3-trisaccharide can be readily accessed. Nanometer-scale molecular architectures presenting as many as 15 sugar moieties in C-5-symmetry are readily produced. The cycloaddition reaction proceeds quantitatively under mild conditions without the need to protect the sugar hydroxyl groups.
A thiolate/alkyl halide coupling reaction in aqueous media provides a one-step synthesis of fullerene glycoconjugates bearing five carbohydrate groups in good yield by using stoichiometric amounts of reactants, without recourse to hydroxy group protection. The sulfide-connection methodology is also useful for synthesis of simpler amphiphilic fullerene molecules, such as one bearing five carboxylic acid groups.