Carbosulfonium ions

Various sulfonium and carbosulfonium ions show remarkably enhanced reactivity upon superelectrophilic activation, similar to their oxygen analogs so do selenonium and telluronium ions. The alkylating ability of their trialkyl salts, for example, is greatly increased by protosolvation. 

A series of thioketones have also been protonated to form carbosulfonium ions 358541,542 and studied by 13C NMR spectroscopy.665 It was found that deshielding of the thiocarbonyl carbon is much less pronounced than that of ketones. This shows that there is significant mercaptocarbenium 358b contribution to the overall protonated thioketone structure. However, this is not the case in the case of protonated ketones. 

Reactive collision gases have also been used in organic MS. Pioneering experiments involved the study of the formation of an adduct ion between protonated esters and ammonia in the collision cell of a TQ instrument [50]. Since then, numerous examples have been reported such as the study of gas-phase reactions of dilactones, psorospermin, and quabalactone diterpenes [51], different phospholipid classes [52], ethyl vinyl ether, the transacetalization with gaseous caiboxonium and carbosulfonium ions by colhsion cell reactions with cyclic acetals and ketals [53], and ketalization of phosphonimn ions using 1,4-dioxane [54]. 

Moraes LAB, Mendes MA, Sparrapan R, Eberlin MN. Transacetalization with gaseous car-boxonium and carbosulfonium ions. J Am Soc Mass Speetrom. 2001 12 14-22. 

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