Thianthrene reaction with phenol

The first thianthrene dication (32) has been isolated. Work on the thianthrene cation radical (33) continues. Its reaction with aliphatic amines yielded the sulphimides (34 X = NR) phenols and aromatic amines were attacked in the pflra-position to afford (34 X = / -HOCeH4 or p-R2NC H4), and enolizable ketones yielded the j8-keto-sulphonium salts (34 X = CHR COR ). The latter compounds reacted with nucleophiles Y to give the a-substituted ketones YCHR COR, and might prove to be useful intermediates for their synthesis. Reinvestigation of the kinetics of the reaction of (33) with phenol and with anisole has provided evidence which appears to disprove the disproportionation mechanism postulated earlier for these reactions. 

Treated with c. HCl (65JOC2145) or c. H2SO4, then ice (63JOC2828), thianthrene 5-oxide gave 2-substituted-products 2-chloro (in low yield) and 2-hydroxythianthrene 5-oxide, the latter being reduced to 2-hydroxythianthrene by subsequent exposure to Sn/AcOH. Thianthrene radical ion(H-) may be produced in each case thus the incorporation of phenol into the HCl reaction gave the 5-(4-chlorophenyl)thianthrenium chloride (65JOC2145) (see Section III, A, 3, b). 

Peroxide complexes of molybdenum(VI) are intermediates in industrially important epoxidation reactions. The so-called Mimoun-type complexes [Mo 0(02)2LaxLeq]° " (12) generally exhibit pentagonal-bipyramidal structures, with an axial 0x0 group trans to Lax and Leq, and two peroxo groups in the equatorial plane. These complexes are effective reagents for the selective oxidation of alcohols to aldehydes, amines to nitroso compounds, sulfldes to sulfoxides and then to sulfones, phenols to o-quinones, and in the sulfoxidation of thianthrene-5-oxide. 

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