Intra- and intermolecular reactions of 2-(2,3-epoxypropyl)-1,3,2-benzodioxaphosphole with some five-coordinate phosphorus halides

Reactions of 2-(2,3-epoxypropyl)-1,3,2-benzodioxaphosphole with bis(o-pheny lenedioxy)chlorophosphorane yield mainly products of beta-cleavage of the o xirane ring, Reactions of 2-(2,3-epoxypropyl)-1,3,2-benzodioxaphosphole wit h dry HCl and HBr result in quantitative formation of stable H-phosphoranes including a 4-halomethyl-1,3,2-dioxaphospholane fragment, Bromination of 2 -(2,3-epoxypropyl)-1,3,2-benzodioxaphosphole with molecular bromine gives 2 ,3-epoxypropyl(o-phenylenedioxy)dibromo as intermediate, in which regiosele ctive intramolecular beta-addition to the oxirane ring affords 2-bromo-4-br omo-methyl-2,2-(o-phenylenedioxy)- 1,3,2-dioxaphospholane. Depending on the reaction conditions, the latter either undergoes cleavage of the dioxaphos pholane ring to form 2-(1,3-dibromo-2-propyl)-1,3,2 lambda(5)-benzodioxapho sphol-2-one or adds to 2-(2,3-epoxypropyl)- 1,3,2-benzodioxaphosphole with formation of bis-phosphoranes or phosphoranyl-containing phosphites.