2.3- Diphenylthiirene 1,1-dioxide

Fluoride ion attacks the sulfur atom in 2,3-diphenylthiirene 1,1-dioxide to give ck-1,2-diphenylethylenesulfonyl fluoride (23%) and diphenylacetylene (35%). Bromide or iodide ion does not react (80JOC2604). Treatment of S-alkylthiirenium salts with chloride ion gives products of carbon attack, but the possibility of sulfur attack followed by addition of the sulfenyl chloride so produced to the alkyne has not been excluded (79MI50600). In fact the methanesulfenyl chloride formed from l-methyl-2,3-di- -butylthiirenium tetrafluoroborate has been trapped by reaction with 2-butyne. A sulfurane intermediate may be indicated by NMR experiments in liquid sulfur dioxide. 

Diphenylthiirene 1-oxide reacts with hydroxylamine to give the oxime of benzyl phenyl ketone (79JA390). The reaction probably occurs by addition to the carbon-carbon double bond followed by loss of sulfur monoxide (Scheme 80). Dimethylamine adds to the double bond of 2,3-diphenylthiirene 1,1-dioxide with loss of sulfur dioxide (Scheme 81) (75JOC3189). Azide ion gives seven products, one of which involves cleavage of the carbon-carbon bond of an intermediate cycloadduct (Scheme 81) (80JOC2604). 

Addition-elimination reactions occur on treatment of 2,3-diphenylthiirene 1,1-dioxide with benzenesulfonate ion or with trisubstituted phosphines (Scheme 86) (75JQC3189). 

The carbon-carbon double bond of 2,3-diphenylthiirene 1,1-dioxide is reduced by aluminum amalgam in wet ether to cis-2,3-diphenylthiirane 1,1-dioxide (16%). 

Electrochemical reduction of 2,3-diphenylthiirene 1-oxide yields acetylene (80%) and benzil (10%). Electrolysis of 2,3-diphenylthiirene 1,1-dioxide in DMF gives trans-stilbene (30%) but in the presence of acetic acid, 1,2-diphenylvinylmethyl sulfone (27%) is obtained in addition to the stilbene (40%) (81CC120). 

Fluoride ion attacks the sulfur atom in 2,3-diphenylthiirene 1,1-dioxide to give m-l, 2-diphenyl-ethylenesulfonyl fluoride (23%) and diphenylacetylene (35%), whereas bromide or iodide ion does not react <80JOC2604>. 

Thiatriazines 1 and 1,3,4,5-thiatriazines 2 are not naturally occurring compounds. The compounds, originally 3 regarded as 2,4,5-trisubstituted 2//-l,2,3,6-thiatriazines 1 were subjected to 13C NMR spectroscopy and crystallographic scrutiny4,5 and shown to possess the structure of symmetrically 2,6-disubstituted 1,3,4,5-thiatriazines 2. In 1980. the first example of a 1,3,4,5-thiatriazine was reported in the oxidized sulfone form 3, formed by the reaction of 2,3-diphenylthiirene 1,1-dioxide with azide ion6 in very low yield. 

Bordwell and collaborators73 have demonstrated that UV irradiation of phenylthiirane 1,1-dioxide (64) affords styrene and sulphur dioxide. The 2,3-diphenyl dioxide (65,66) (as a mixture of cis and trans isomers) also decomposes and affords a mixture of cis and trans stilbene. Loss of S02 occurs on irradiation of 2,3-diphenylthiirene-1,1-dioxide (67) in methanol giving diphenylacetylene in 93% yield74. The photodecomposition of three-ring compounds has been reviewed75. 

The reaction of 2,3-diphenyl- or 2,3-bis-(4-chlorophenyl)-thiiren 1,1-dioxide with enamines R R C=CR NR 2 yields a variety of heterocyclic compounds, including medium- and large-ring sulphur heterocycles, via decomposition of a bicyclic thiiran dioxide intermediate (26). Treatment of these thiiran dioxides with 2-pyrrolidinyl- or 2-piperidinyl-2-norbornene gave adducts which possessed antifertility activity. The reaction of 2,3-diphenylthiiren 1,1-dioxide with several meso-ionic compounds, e.g. (27), gave 2,3,5,6-tetraphenyl-4 -l,4-thiazine 1,1-dioxides by loss of carbon dioxide from the intermediate adduct (28). ... 

A variety of nucleophiles add to the double bond of 2,3-diphenylthiiren 1,1-dioxide to give mainly ring-opened products. The principal mode of fragmentation of thiiren oxides and dioxides in mass spectrometry involves elimination of SO or SOj. Fragmentation of 2,3-diphenylthiiren 1-oxide is also believed to involve rearrangement to monothiobenzil. ... 

The reaction of 2,3-diphenylthiiren 1,1-dioxide (8) with enamines derived from cyclic ketones gives rise to ring-enlargement products such as (9), which contain the divinyl sulphone unit e.g. the reaction of l-(l-cyclohexen-l-yl)-pyrrolidine (10) with the above thiiren gave (9 n = 1), in 86% yield. The ten-and thirteen- to fifteen-membered-ring analogues were also prepared from the... 

Treatment of 2,3-diphenylthiiren 1,1-dioxide with acyl-substituted sul-phonium ylides gives a thiet dioxide (123), an oxathiin dioxide (124), and a dithiin (125). An intermediate acyl thiiran 1,1-dioxide was suggested. The pyridinium ylide (126) gave 3-benzoyl-1,2-diphenylindolizine (127). ... 

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