Cyclic organophosphorus compounds. Part XIII. Stereospecific formation of 4-substituted 1,3,2-dioxaphosph(V)orinans from bicyclic phosphorus(III) esters

2,7,8-Trioxa-1-phosphabicyclo[3,2,1]octane and its 4,4-dimethyl derivative have been prepared by transesterification. Both compounds undergo stereospecific ring opening when treated with benzyl or triphenylmethyl chlorides, methyl toluene-p-sulphonate, N-chloropiperidine, or N-chloromorpholine. Attempts to prepare 2,6,7-trioxa-1-phosphabicyclo[2,2,1]heptane have been unsuccessful.