Anishchenko V. Inverse phase-transfer catalysis and reagents structure in reaction between phosphoryl chloride and phenols

Inverse phase-transfer catalysis (IPTC) was used to perform reaction between reagents in two-phase medium water/dichloromethane. (N-diphenoxyphosphoryloxy)-4-dimethylaminopyridinium chloride, perchlorate and tetraphenylborate were synthesized to confirm that reaction paths through ionic intermediate. Structure of synthesized salts were confirmed with IR and NMR spectroscopy The extended scheme of process that includes formation of tetraphenyl pyrophosphate was proposed based on the collected experimental data. Reaction rate constants of interaction between pyridine N-oxides and diphenyl phosphoryl chloride for different temperatures were determined using equations based on proposed scheme. It was found that the process of phosphorylation at 5 °C using dimethylaminopyridine N-oxide possible to achieve almost quantitative yield the desired product. According to the simulation of reaction between diphenyl phosphoryl chloride and pyridine-N-oxides transition state have geometry of triangular bipyramid and Gibbs free energy of activation essentially depends on the conformation of diphenyl phosphoryl chloride. Several phosphates were synthesized with using IPTC method and optimal reaction condition. The structure of the synthesized compounds was confirmed by IR and NMR spectroscopes'. The influence of spatial arrangement of substituent on vibrational frequencies and shielding of 31P were determined by analysis of the calculated IR and NMR spectra.