Reactions of 5-oxo-2,2,2-triphenylbenz[c]-1,2-oxaphospholane with Grignard reagent and hydriodic acid. Thermolysis of triphenyl-(o-carboxyphenyl)-phosphonium iodide

Triphenyl(o-carboxyphenyl)phophonium iodide (1) is formed with the yield of 99 % when first hydrogen chloride and then potassium iodide react with 5-oxo-2,2,2-triphenylbenz[C]-1,2-oxaphospholane. In contrast to the Grignard reagent hydriodic acid splits P-O bond in phospholane (2) and compound 1 is formed. Thermolysis of 1 is accompanied by intramolecular elimination of carbon dioxide and formation of tetraphenylphosphonium iodide