Oxidation of Cyclic Oligosulfides and Structures and Decomposition Reactions of the Oxides

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1. The chemistry of Dithiiranes. (i) The reaction of S_8O, prepared by oxidation of elemental sulfur, with diazo compounds yielded the desired dithiirane 1-oxides. (ii) The dithiirane 1-oxides were reduced with Lawesson's reagent to give unoxidized dithiiranes. (iii) The reaction of the dithiirane 1-oxides and the dithiiranes thus obtained with (Ph_3P)_2Pt(C_2H_4) produced the Pt-insertion products in high yields.2. The chemistry of tetrathiolanes. (i) Oxidation of a tetrathiolane with dimethyldioxirane (DMD) gave the 2-oxide and then 2,3-dioxide. The 2,3-dioxide decomposed in solution over -20℃ to give the dithiirane 1-oxide and disulfur monoxide. (ii) The reactions of the 2-oxide and the 2,3-dioxide with (Ph_3P)_2Pt(C_2H_4) produced the identical Pt-S_2O complex. The Pt-S_2O complex further reacted with (Ph_3P)_2 Pt(C_2H_4) to give the novel platinum dinuclear complex in high yield.3. The chemistry of pentathianes. (i) Oxidation of a pentathiane with trifluoroperacetic acid and DMD g … More ave the 3-oxide and the 1-oxide, respectively. (ii) The reaction of the 3-oxide with (Ph_3P)_2 Pt(C_2H_4) yielded the cyclic (dithiolato-thiolato)-Pt complex and the Pt-S_2O complex in high yields.4. The chemistry of 1,2,4-trithiolanes. (i) a cis-tetrasubstituted 1,2,4-trithiolane was allowed to react with DMD to give two 1-oxides. Oxidation of one of the 1-oxides yielded the desired 1,2-dioxide, while that of the other 1-oxide gave the 1,1-dioxide. The 1,1-dioxide decomposed in solution at room temperature to give two molar equiv of the thioketone. Similarly, the 1,2-dioxide decomposed to two molar equiv of the thioketone in refluxing chloroform, while the two 1-oxides decomposed to the identical thiirane in refluxing xylene. (ii) Oxidation of a trans-tetrasubstituted 1,2,4-trithiolane with MCPBA produced two 1-oxides. Further oxidation of one of the 1-oxides with DMD yielded two diastereoroeric 1,2-dioxdes and 1,1-dioxide, while that of the other 1-oxide gave only one of the 1,2-dioxides. We observed equilibrium between the two 1,2-dioxides. Less