%0 Journal Article %A Destro, Riccardo %A Lucchini, Vittorio %A Modena, Giorgio %A Pasquato, Lucia %D 2000 %T X-ray Structures and Anionotropic Rearrangements of Di-tert-butyl-Substituted Thiiranium and Thiirenium Ions. A Structure−Reactivity Relationship %U https://acs.figshare.com/articles/journal_contribution/X-ray_Structures_and_Anionotropic_Rearrangements_of_Di-_i_tert_i_-butyl-Substituted_Thiiranium_and_Thiirenium_Ions_A_Structure_Reactivity_Relationship/3720507 %R 10.1021/jo991731o.s001 %2 https://acs.figshare.com/ndownloader/files/5812203 %K butyl groups %K trans tert %K thietanium ion %K BF %K thietium ion %K Anionotropic Rearrangements %K steric hindrance %K 8 SbCl 6 %K Thiirenium Ions %K 11 SbCl 6 %K methylthiiranium %K rearrangement %K intramolecular S N 2 displacements %X The X-ray structures of c-2,t-3-di-tert-butyl-r-1-methylthiiranium 8 BF4-, t-2,t-3-di-tert-butyl-r-1-methylthiiranium ion 10 BF4-, and 2,3-di-tert-butyl-1-methylthiirenium 11 BF4- have been determined. The ΔG298 values for the rearrangements from the cis and the trans tert-butyl groups of 8 SbCl6- to thietanium ion (two intramolecular SN2 displacements) and for the rearrangement of 11 SbCl6- to thietium ion (an intramolecular SN2-Vin displacement) are linearly correlated with the strengths of the C−S breaking bonds, suggesting that the two mechanisms are, in the absence of steric hindrance, uniquely governed by the nucleofugality of the sulfonium leaving group. %I ACS Publications