2,2,2-Trichloro-4-methoxy-1,3,2-benzodioxaphosphole in the reactions with terminal acetylenes

2,2,2-Trichloro-4-methoxy-1,3,2-benzodioxaphosphole reacts with arylacetylenes or 3-chloropropyne to give 2,7-dichloro-5-methoxy-4-aryl(haloalkyl)-1,2-benzoxaphosphinine 2-oxides. Hydrolysis of the latter leads to the opening of the oxaphosphinine ring and formation of (E)-2-(4-chloro-2- methoxy-6 hydroxyphenyl)ethenylphosphonic acid.