Tuning the Structure of 4‐Aminopyridine Catalysts for Improved Activity and Selectivity in Functionalization of Alcohols

Abstract

AbstractSeeking to improve the site selectivity in the catalytic phosphorylation and acylation of a model amphiphilic substrate, further increasing the preference for the apolar domain, which we recently disclosed, we attempted to augment the nucleophilicity of the 4‐aminopyridine core unit used in our catalysts, while simultaneously preserving or even increasing the density of their lipophilic outer‐sphere components. Of the three approaches to the new catalyst design, the most promising, in the case of phosphorylation, was that placing two benzyl moieties, substituted with long apolar alkoxy groups in the ortho positions, on the amine nitrogen of the core. This modification also substantially improved the activity of the catalyst in both reactions. Although this approach reduced the selectivity in the acylation reaction, we demonstrated that by altering the geometry of the benzyl substituents (e. g., by restricting the degree of their freedom), the higher selectivity can be regained.