α-Diazosulphones and related compounds from the base-induced cleavage of α-diazo-β-ketosulphones

Abstract

Acylsulphonyldiazomethanes undergo acyl cleavage when treated with triethylamine in dry methanol to give α-diazosulphones (ca. 30%). The poor yields are ascribed to base-promoted decomposition of the diazosulphone during the work-up procedure since the addition of triphenylphosphine prior to work up gave sulphonylformaldehyde hydrazones (70—80%), a previously unknown class of compounds, which arose by hydrolysis of the first formed phosphazine. The acylsulphonyldiazomethanes were prepared by the action of toluene-p-sulphonyl azide and triethylamine on β-ketosulphones in 60% aqueous ethanol. If the diazoketosulphone is retained in solution and the reaction period prolonged, sulphonylformaldehyde hydrazones may be isolated directly, following the addition of triphenylphosphine.