Generation of new dithia dications from sterically congested 1.9-dithiodibenzothiophenes and their monooxides in concentrated sulfuric acid
摘要:
1,9-Dithiodibenzothiophenes 2 were prepared by ring contraction of 4,6-dithiothianthrene-5-oxides with n-butyllithium. Both compounds 2 and their monooxides 3 upon dissolution in conc. H2SO4 afforded the corresponding new dithia dications. Electrochemical oxidation of 2 provides the evidence for the neighboring group interaction between the two 1,9-sulfenyl sulfur atoms.
A Convenient Preparation of Sterically Crowded 1,9-Disubstituted Dibenzothiophenes and 3,3'-Disubstituted Diaryl Sulfides
摘要:
Thianthrene-5-oxide (1) reacted with 2.2 equivalents of lithium diisopropylamide to give 4,6-dilithiated 1 which was converted to 4,6-disubstituted thianthrene-5-oxides (3). 3 afforded sterically crowded 1,9-disubstituted dibenzothiophenes (4) in moderate yields on treatment with n-butyllithium or phenyllithium.