The synthesis, stereochemistry, and crystal structure of exo-3-p-nitrobenzyl-endo-3-phenyl-3-phosphoniabicyclo[3.2.1]octane bromide

Abstract

The synthesis of the title compound is described. C₂₀H₂₃BrNO₂P crystallizes in the monoclinic space group P2₁/c with cell constants a= 12.934(1), b= 8.996(1), c= 17.622(3)Å, β= 106.74(1)°, Z= 4. The structure was solved by the heavy-atom method and refined to an R value of 0.046. The phosphorinanium ring adopts a chair conformation which is substantially flattened at the phosphorus end. The study confirmed the endo- and exo-disposition of phenyl and p-nitrophenyl substituents, respectively. The ring conformation, bond lengths, and angles as well as torsional angles are compared to calculated values of the silicon analogue; there is close similarity.