Reaction of (phenylenedioxy)trihalophosphoranes with arylacetylenes: VI. Regiochemistry of the reaction of 2,2,2-trihalo-5-methylbenzo[d][1,3,2] dioxaphospholes with arylacetylenes

NMR and IR spectroscopy and X-ray diffraction were used to show that the reaction of 2,2,2-trichloro- and 2,2,2-tribromo-5-methylbenzo[d][1,3,2]dioxaphospholes with para-substituted arylacetylenes proceeds with regioselective formation of 4-aryl-2-halo-7-methyl-2-oxobenzo[e][1,2]oxaphosphorines. With the trichlorophosphole, selective chlorination of the phenylene fragment in the para position to the endocyclic oxygen atom occurs. With the tribromophosphole, 6-bromo- and unsubstituted benzo[e][1,2]oxaphosphorines are formed as major products. The molecular and supramolecular structure of some of the obtained oxaphosphorines was studied by X-ray diffraction.