Conformational and configurational analysis of 2-phenoxy-2-oxo-1,3,2-dioxaphosphorinanes. Conformational and configurational dependence upon conformation of the diol precursor

Diastereomeric 5-tert-butyl-4-methyl-2-phenoxy-2-oxo-1,3,2-dioxaphosphorinanes were synthesized, and studied by NMR and computational methods in order to determine their predominant conformations as well as their relative configurations. The study was performed assuming a novel criteria, in which, the conformation and configuration of the diastereomeric 5-tert-butyl-4-methyl-2-phenoxy-2-oxo-1,3,2-dioxaphosphorinanes depend upon the conformation of the corresponding diol precursors. In other words, the orientation or pseudo orientation of the groups into the ring framework of the heterocyclic is initially acquired by the direct phosphorylation reaction with the diol precursor in the most stable conformation, and then, once the heterocyclic is formed, the final conformation is dictated by stereoelectronic and steric effects.