Thiirane 1,1-dioxides compounds

Thiirane oxides (3 x = 1) were rather rare and not well characterized until about 20 years ago20. Since 1965 synthetic methods for their preparation have been consistently and systematically explored2. They are rather thermodynamically stable compounds— compared to their closely-related thiirane dioxides—provided they have an anticonfiguration with respect to the substituents and the sulfinyl oxygen. Also they are more resistant than the corresponding sulfones toward ring opening by either nucleophiles or electrophiles. 

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). ... 

Thiirane is more bactericidal than oxirane, and derivatives of 2-mei captomethylthiirane inhibit tuberculosis. The following pharmacological uses have been reported for compounds derived from thiirane derivatives gold complexes of the adducts of diethylphosphine and thiirane (antiarthritic), adducts of thiiranes and malononitrile (antibacterial, blood vessel dilators, muscle relaxants, sedatives), thermolysis products of thiirane 1-oxides and adducts of thiirane 1-oxides with sulfenyl chlorides (antibacterial), adducts of 2,3-diarylthiirene 1,1-dioxides with ynamines (antibacterial, parasiticidal), adducts of 2,3-diarylthiirene 1,1-dioxides with enamines (antifertility), adducts of p-aminophenylacetic esters with thiirane (immunosuppressants), adducts of amines and thiiranes (radioprotective drugs). 

Small ring compounds represent a fair portion of strained organic systems in which the geometry of sp and that of sp carbons have been distorted from the ideal configurations. Foremost among these reactive molecules are the small ring heterocycles, such as thiirane and thiirene oxides and dioxides. ... 

A characteristic property of thiirane 1,1-dioxides is the ease with which such molecules fragment into sulfur dioxide and the related olefin on standing for several hours at room temperature. The title compound is no exception however, the rate of decomposition may be reduced substantially by storage under an inert atmosphere in a freezing compartment (ca. —5°). Under such conditions the product may be kept for many months. 

Thiirane A,A-dioxides are quite unstable and are difficult compounds to make. The first stable thiirane A,A-dioxide was synthesized by oxidation of a thiirane using a mixture of Oxoneu/trifluoroacetone (Oxone = 2KHSO5KHSO4K2SO4) (Scheme 63) <1997TL5873>. 

Another example which illustrates the importance of the structure of the diazoalkane in reactions of thiocarbonyl compounds and derivatives thereof is the reaction of trithiocarbonate S,S-dioxide 6 with diazomethane and phenyldiazomethane52. Whereas the former gives the dithiolane derivative 7, the latter affords the thiirane 8. Both reactions are, however, fully stereoselective affording single diastereomeric compounds the most probable structures are depicted in the scheme. 

Unlike episulfides, the related episulfones (or thiirane S-dioxides) are usually very unstable. Interest in these compounds centered mainly on their proposed intermediacy in the Ramberg-Backlund reaction of a-halosulfones with strong bases to give alkenes - , viz. 

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