On the molecular structure and geometry of pyridylalkylamine–H+ complexes: application to catalytic enantioselective hydroxyalkylation of indoles†
Abstract
The protonation of 2-pyridylalkylamines (PAA) was investigated through quantum chemical calculations at a DFT level of theory in dichloromethane solution. Two different PAA–H+ species and a dynamic equilibrium between protonated forms were evidenced. The overall geometry of the PAA–H+ promoters is strongly influenced by the nature of the moiety and the absolute configuration of the pseudobenzylic stereocenter. Thus, PAA–H+ complexes were used as organocatalysts in the enantioselective hydroxyalkylation of