The Chemistry of Thiiranium Ions

The Chemistry of Thiiranium Ions. - The chemistry of episulphonium ions and the reactions of alkenes with sulphenyl derivatives have been reviewed Stable thiiranium and thiirenium chlorides have been generated in S02. Kinetic studies for the quantitative generation of (329 R =R = Bu, X = Cl) from the ionization of (328) and the equilibrium between (330) and (331) in SO2 were followed, using n.m.r. spectrometry. Compounds (329 R = Bu, X = SbCls or BF4) have been isolated as stable salts at room temperature 

---

The Chemistry of Thiiranium Ions.- Reaction of ArSSAr (Ar=Ph, 4-ClCgH, 4-MeCgH, 2,436-Me CgH2) with ArSCl and/or SbCl,. gave (328) which with alkenes yields S-aryl thiiranium ions eg. (329) from norbomene242. Stable S-aryl... 

The reactions of thiiranes with electrophiles has been extensively studied and well reviewed <83HC(42/l)333,84CHEC-I(7)i3i>. Generally, electrophilic additions to thiiranes may be stereoselective and result in both Markovnikov and anti-Markovnikov ring-opened products from unsymmetrical thiiranes. The nature of the products in terms of stereochemistry and mode of addition are reflective of cyclic (thiiranium or episulfonium ion) and open-chain (carbocation) intermediates. The generation and chemistry of episulfonium ions has been reviewed in detail and is not elaborated further here thiiranes with electrophiles. 

A book on the chemistry of thiirans has been published and two reviews on thiiranium ions have appeared. 

---