Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 12.1 Extrusion of Ph3P from sulfonyl ylides and reactivity of the resulting sulfonyl carbenes

Abstract

Twelve sulfonyl stabilised phosphorus ylides have been prepared and their behaviour upon flash vacuum pyrolysis at 600 °C has been examined. Examples with an arylsulfonyl substituent undergo loss of Ph₃PO to give intractable products but those with an arylmethylsulfonyl substituent separately lose Ph₃P and SO₂ to give products consistent with the intermediacy of sulfonyl carbenes. X-Ray structure determinations of one ylide from each series show a more significant P–O non-bonding interaction in the first case, providing some explanation for the different thermal reactivity.