Thietane 1,1-dioxides reactions

Although the yields of the above reactions are high and the procedure is simple186, there are some apparent disadvantages the selection of the sulfene substituents R1 and R2 is limited, depending on the availability of the sulfonyl chloride precursors the cycloaddition leads to a mixture of cis- and trans-substituted thietane dioxides the cycloaddition reaction is reversible202 and several further transformations are necessary if a dioxide without 3-lV-substituent is required. 

The preparation and investigation of the thietane oxide system (5a) is largely associated with stereochemical and conformational studies . The investigation of the thietane dioxides (5b) is substantially related to the chemistry of sulfenes , the [2 -I- 2] cycloaddition of which with enamines is probably the method of choice for the synthesis of 5b . The study of the thiete dioxide system (6) evolved, at least in part, from the recognition that the unstable thiete system 183 can be uniquely stabilized when the sulfur in the system is transformed into the corresponding sulfone , and that the thiete dioxide system is very useful in cycloadditions and thermolytic reactions. The main interest in the dithietane oxides and dioxides (7) appears to lie in the synthetic challenge associated with their preparation, as well as in their unique structural features and chemical behavior under thermolytic conditions . ... 

Alkylidene sulfenes (75), generally prepared by the dehydrohalogenation of alkylsulfonyl chlorides, add readily to electron-rich multiple bonds. For example, with enamines, the thietane dioxide (e.g., 76) is formed diazoalkanes yield thiirane dioxides (episulfones) and imines (Schiff bases) afford 1,2-thiazetidine 1,1-dioxides. There are available numerous reviews of sulfenes, including cycloaddition reactions.102... 

One of the most widely applied cycloaddition techniques for the preparation of thietanes is the reaction of sulfenes with enamines. The stereochemistry of these reactions has been extensively investigated by Truce and Rach. Whether the mechanism is a two-step or a concerted process, both in accordance with the stereoselective formation of the cis form in Scheme 1, is still unresolved. The special orientation of the 1,4-dipolar intermediate 64, in which the charged phenyl and dimethylamino moieties are in proximity, enforces the cis geometry of the resulting thietane dioxide. In the concerted mode of reaction, formation of the orthogonal oriented unsaturated system, 65 should also yield the cis cycloadduct. 

Simple unsaturated sulfides cannot be used in place of enamines in cycloaddition reactions with sulfines leading to thietane dioxide derivatives. " Alkyl, vinyl, and cycloalkylvinyl sulfides, which carry a C=C double bond, are considerably less nucleophilic than the enamines and thus do not partake in cycloadditions to sulfene. But when the more electrophilic methylsulfonyl sulfene is used in association with an unsaturated sulfide substituted with a strong electron donating alkylamino group, the formation of thietane dioxides 72 is successful. 

An interesting variation to cycloadditions involving sulfenes is a reaction carried out with a-amino ketoximes, by which thietane dioxides are produced. The authors suggested a two-step mechanism via the intermediate cyanoenamine 83. Higher yields were obtained when the oximes were... 

The first diradical intermediate is the same as that involved in the photolysis and thermolysis of thietane l,l-dioxides ° and interconversion of the y-sultine and thietane dioxide often accompanies cyclopropane formation. In flash-vacuum pyrolysis, formation of the alkene may compete with the desired cyclopropane-forming reaction. Examples of this reaction are summarized in Table 11. 

Enamines reaction with methanesulphonyl chloride and its homologues in the presence of triethylamine to yield thietane 1,1-dioxides. Thus 1-morphoIinocyclohexene gives a bicyclic thietane dioxide and 2-methyl-l-pyrrolidinopropene and other enamines derived from aliphatic aldehydes react analogously (equation 1). It is thought that the reactions proceed by way of the unisolable sulphene 1, which adds to the enamine double bond in a stepwise or concerted manner. This question has been much debated (for a critical discussion, see Reference 2, p. 3386) and will not be pursued here. It has been found that there is a lack of stereoselectivity in the addition of sulphene to the conformationally rigid enamines derived from 4-t-butylcyclohexanone . 

Addition of sulphenes to electron-rich alkenes is a well-known route to thietan dioxides.Iminosulphenes are intermediates in base-promoted reactions of... 

Thermolysis and Photolysis of Thietan Dioxides. These reactions frequently lead non-stereospecifically to cyclopropanes and olefins, the relative yields of which vary markedly with the constitution of the thietan... 

Paquette et alf have shown that the well-known reaction of sulphenes with vinyl amines to form thietan dioxides is amenable to asymmetric induction. The reaction of the parent sulphene with electronegatively substituted carbonyl compounds can follow two courses (see Scheme 1),... 

B. 3-Chlorothietane 1,1-dioxide. Thietane 1,1-dioxide (14.0 g, 0.132 mol) is placed in a three-necked, 500-mL, round-bottomed flask fitted with a magnetic stirrer, reflux condenser and a chlorine bubbler, caution sinae ahtovine is poisonous, the reaation involving it should be done in a good hood.) Carbon tetrachloride (300 mL) is added to the flask (Note 4) and the suspension is irradiated by a 250-watt sunlamp positioned as close as possible to the reaction flask without touching it (Note 5) while chlorine is bubbled through the solution for 15 min at a moderate rate (Note 6). A copious white precipitate forms and irradiation and addition of chlorine must be stopped at... 

D. 3,3-Diahlarothietane 1,1-dioxide. Thietane 1,1-dioxide (5.0 g, 0.047 mol) Is placed In a 500-mL, three-necked, round-bottomed flask equipped with a reflux condenser, magnetic stirrer, and chlorine gas bubbler. Carbon tetrachloride (350 mL) Is added and the solution Is irradiated with a 250-watt sunlamp (Note 5) while chlorine Is bubbled through the stirred mixture for 1 hr (Note 9). Irradiation and chlorine addition are stopped and the reaction mixture is allowed to cool to room temperature. The product Is collected by filtration as a white solid (4.0-4.4 g, 49-53%), mp 156-158°C (Note 10). The product can be used without further purification or It can be recrystallized from chloroform. 

Selective chlorination of the 3-position of thietane 1,1-dioxide may be a consequence of hydrogen atom abstraction by a chlorine atom. Such reactions of chlorine atoms are believed to be influenced by polar effects, preferential hydrogen abstraction occurring remotely from an electron withdrawing group. The free radical chain reaction may be propagated by attack of the 3-thietanyl 1,1-dioxide radical on molecular chlorine. 

The following compounds have been obtained from thiete 1,1-dioxide Substituted cycloheptatrienes, benzyl o-toluenethiosulfinate, pyrazoles, - naphthothiete 1,1-dioxides, and 3-subst1tuted thietane 1,1-dioxides.It is a dienophile in Diels-Alder reactions and undergoes cycloadditions with enamines, dienamines, and ynamines. Thiete 1,1-dioxide is a source of the novel intermediate, vinylsulfene (CH2=CHCH=SQ2). which undergoes cyclo-additions to strained olefinic double bonds, reacts with phenol to give allyl sulfonate derivatives or cyclizes unimolecularly to give an unsaturated sultene. - Platinum and iron complexes of thiete 1,1-dioxide have been reported. 

The reaction of Af,Af-dimethyl-( )-styrylamine (73) with a halogen-substituted methanesulfonyl chloride allowed the first stereoselective formation of the halogenated thietane 1,1-dioxide 74, which then could be converted to the corresponding thiete sulfone 75 via a Cope elimination of the corresponding AT-oxide. ... 

The susceptibility of the thiete 1,1-dioxides to nucleophilic addition reactions can be utilized to produce 3-substituted thietane derivatives. For example, the thus easily attainable 3-cyano and 3-nitroalkyl-substituted derivatives could be reduced to the 3-aminomethylthietanes ° (Eq. 61). 

Treatment of 3-hydroxythietanes 21b-g with aqueous sodium hydroxide led to retro-aldol ring cleavage to produce the carbonyl derivatives 23b-g (Table 1) <1997J(P2)425>. It was proven that the rate of the reaction was determined by the nature of the substituent at the 3-position and by the oxidation state of sulfur. 3-Phenylthietane-3-ol 21b underwent retro-aldol reaction to give sulfide ketone 23b. Thietane-l-oxide-3-ol 21c-e or thietane-l,l-dioxide-3-ol 2 If and 21g derivatives underwent retro-aldol reaction to produce carbonyl sulfoxides 23c-e and carbonyl sulfones 23f and 23g (Table 1) <1997J(P2)425>. 

The treatment of bis(trimethylsilanyl)methanesulfonyl chloride with triethylamine led to the formation of a sulfene 89, which upon reaction with diethyl ketene acetal gave a thietane adduct 90. The latter led to thiete 1,1-dioxide 91 in very poor yield (5%) after the loss of trimethylsilyl ethoxide (Equation 29) <2000CJC1642>. 

An interesting transformation has been reported by Burlingham and Widlanski <2001JA2937>, who synthesized fused-ring thietane-1,1-dioxide 115, in 38% yield, by the reaction of iV-benzyl dimethyldisulfonimide 113 with the morpholine derivative 114 in the presence of butyllithium (Equation 33). 

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