Substrate and Product Selective Supramolecular Catalysis by Pillar[5]arene in the Alkylation of Primary Linear Amines with Allyl Bromide

We report the supramolecular catalysis exerted by the cavity of pillar[5]arene on the classic nucleophilic substitution reaction of primary alkyl amines on allyl bromide. The tubular nanocatalyst imparts both substrate selectivity for linear amines and product selectivity in favor of secondary amine products. The reaction turned out to be very sensitive to the size of the cavity and the nature of the alkoxy residues on the rim of the cylindrical nanometric catalyst. The acceleration observed was due to the stabilization of the developing charge on the N atom by an electrostatic interaction with the aromatic units of the cavity of the pillararene. Recycling of the supramolecular organocatalyst was also demonstrated.