Phenylnitrile oxide as well as mesitylnitrile oxide underwent 1,3-dipolar cycloaddition reactions with the 1,3,5-triphosphinines 2 under mild conditions to furnish the condensed heterocyclic compounds 9 and 11, respectively. Oxadiphospholes 14 were accessible by fragmentation reactions of 11.
phosphorus - 1,3-dipolar cycloadditions - nitrile oxides - 1,2,4-oxazaphospholes - 1,2,4-oxadiphospholes