Efficient generation of thionitrosoranes (ArNS) by fragmentation of N-(arylaminothio)phthalimides

Base-induced fragmentation of a series of N-(arylaminothio)phthalimides (3) provides an efficient route to transient thionitrosoranes (2); compounds (2) have been trapped as Diels–Alder cycloadducts with butadiene and 2,3-dimethylbutadiene, or as ene adducts with alkenes.