Reactions of phosphonium, sulphonium, and pyridinium ylides with sulphur monoxide

Abstract

Sulphur monoxide generated in situ by smooth thermolysis of trans- 2,3-diphenylthiiran 1-oxide reacts with triphenylphosphonium-, diphenylsulphonium-, and pyridinium-tetraphenylcyclopentadienylide, leading in all cases to tetraphenylcyclopentadienethione S-oxide. Similar reactions with other representative ylides have been investigated. The reactions are very sensitive to the stability of the ylide and to the electronic nature of the groups directly attached to the ylidic carbanion.