Phosphorylation of 2-azabicyclo[2.2.1]hept-5-ene and 2-hydroxy-2-azabicyclo[2.2.1]hept-5-ene systems: synthesis and mechanistic study

Abstract

The endo and exo isomers of (±)-methyl 2-hydroxy-2-azabicyclo[2.2.1]hept-5-ene-3-carboxylates and the in situ-prepared endo and exo isomers of (±)-methyl 2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate were treated with diphenylphosphinic chloride (OPClPh₂) and chlorodiphenylphosphine (ClPPh₂) to afford the corresponding phosphorylated bicycles. The structure of all these compounds was unequivocally determined by NMR spectroscopy and mass spectrometry, and, based on the results obtained, a mechanistic scheme for the phosphorylation reaction of these adducts to afford the corresponding phosphorylbicycles is proposed.