10.1021/jo0354591.s006 Hideaki Oshida Hideaki Oshida Akihiko Ishii Akihiko Ishii Juzo Nakayama Juzo Nakayama Oxidation of <i>cis</i>- and <i>trans</i>-3,5-Di-<i>tert</i>-butyl-3,5-diphenyl-1,2,4-trithiolanes:  Isolation and Properties of the 1-Oxides and the 1,2-Dioxides American Chemical Society 2004 DMD 20 isomerized CDCl 3 295 K Dioxide 3 O chloroperbenzoic acid Oxidation dioxide BF 4 biradical mechanism MCPBA tran oxide butyl tert 2004-03-05 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Oxidation_of_i_cis_i_and_i_trans_i_3_5_Di_i_tert_i_butyl_3_5_diphenyl_1_2_4_trithiolanes_Isolation_and_Properties_of_the_1_Oxides_and_the_1_2_Dioxides/3347557 Oxidation of <i>trans</i>-3,5-di-<i>tert</i>-butyl-3,5-diphenyl-1,2,4-trithiolane with dimethyldioxirane (DMD) or <i>m</i>-chloroperbenzoic acid (MCPBA) gave two stereoisomeric (1<i>S</i>*,3<i>S</i>*,5<i>S</i>*)- and (1<i>R</i>*,3<i>S</i>*,5<i>S</i>*)-1-oxides (<b>16</b> and <b>17</b>, respectively). Oxidation of <b>16</b> with DMD gave the (1<i>S</i>*,2<i>R</i>*,3<i>S</i>*,5<i>S</i>*)-1,2-dioxide (<b>18</b>) and the 1,1-dioxide <b>19</b>, and that of <b>17</b> yielded the (1<i>R</i>*,2<i>R</i>*,3<i>S</i>*,5<i>S</i>*)-1,2-dioxide (<b>20</b>) mainly along with <b>18</b> and <b>19</b>. The structures of the 1,2-dioxides <b>18</b> and <b>20</b> were determined by X-ray crystallography. 1,2-Dioxides <b>18</b> and <b>20</b> isomerized to each other in solution, and the equilibrium constant <i>K</i> (<b>20</b>/<b>18</b>) is 19 in CDCl<sub>3</sub> at 295 K. The kinetic study suggested a biradical mechanism for the isomerization. Isomerization of <b>16</b> and <b>17</b> to <i>cis</i>-3,5-di-<i>tert</i>-butyl-1,2,4-trithiolane 1-oxides by treatment with Me<sub>3</sub>O<sup>+</sup>BF<sub>4</sub><sup>-</sup> is also described.