![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The dithionitronium cation (SNS+) has been shown to undergo completely general, concerted cycloadditions with a wide variety of unsaturated main-group species to give heterocyclic products in quantitative yields. The isolobality of the frontier molecular orbitals of the dichlorothionitronium cation (ClSNSCl+) with those of SNS+ led us to predict that this cation would undergo concerted cycloadditions under similar conditions. This has been confirmed in its reactions with acetylene and ethylene. Dichlorothionitronium hexafluoroarsenate(V) (ClSNSCl+AsF6 -) reacts with acetylene in liquid sulphur dioxide to produce 1,3,2-dithiazolium hexafluoroarsenate(V) quantitatively via initial cycloaddition followed by SO2-mediated chlorine abstraction and aromatisation. Analogously, cycloaddition also occurs with ethylene, though without subsequent chlorine abstraction. This has enabled a novel 1,3-dichloro-1,3,2-dithiazolidinium salt to be isolated in quantitative yield. The characterisation of this product by a variety of spectroscopic techniques will be discussed, together with recent developments in the chemistry of this and related systems.