Simultaneous Formation of Cage and Spirane Pentaalkoxyphosphoranes in Reaction of 5,5-Dimethyl-2-(2-oxo-1,2-diphenylethoxy)-1,3,2-dioxaphosphorinane with Hexafluoroacetone

The reaction of hexafluoroacetone with 5,5-dimethyl-2-(2-oxo-1,2-diphenylethoxy)-1,3,2-dioxaphosphorinane occurs in two simultaneous directions: through the formation of cage phosphorane and spirophosphorane-1,1-(2,2-dimethylpropylenedioxy)-4,5-diphenyl-3,3-bis(trifluoromethyl)-2,6,7-trioxa-1-phosphabicyclo[2.2.1(1.4)]heptane and 2-(2,2-dimethylpropylenedioxy)-2-hexafluoroisopropoxy-4,5-diphenyl-1,3,2-dioxaphospholene, respectively. The latter was obtained by authentic synthesis from 2-hexafluoroisopropoxy-5,5-dimethyl-1,3,2-dioxaphosphorinane and benzil. The mild hydrolysis of the compounds obtained leads to the formation of cyclic phosphates. The structure of the obtained compounds was determined by the NMR and mass spectrometry methods.