Synthesis of Dendrimers via Staudinger/Aza-Wittig Reaction of Frechet-Type Dendritic Benzyl Azides and Frechet-Type Dendritic Benzaldehydes

摘要

A synthetic strategy for dendrimers was developed using Staudinger/aza-Wittig reaction with an aldehyde and an azide in the presence of triphenylphosphine, followed by the reduction of imine intermediates. A fusion method between Frechet-type dendritic benzaldehydes and Frechet-type dendritic benzyl azides led to the formation of first-through fourth-generation dendrimers containing secondary amine as a connector in high yields. Further, fusion coupling using different generation dendrons afforded, efficiently, the unsymmetrical dendrimers. The obtained dendrimers were characterized by the analyses of~1H and ~(13)C NMR spectroscopy, 1R spectroscopy, mass spectra, and gel permeation chromatography (GPC) analysis.