Thietane 1,1-dioxides synthesis

Chiral thietane dioxides, synthesis of 449 Chiral thiete dioxides, synthesis of 449 Chlorine compounds, as oxidizing agents... 

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 . ... 

Application of the enamine-sulfene cycloaddition allowed the synthesis of 78 and 79 from the corresponding a,/l-unsaturated amines and sulfenes. Similarly, using enamine 80, the crystalline morpholino thietane dioxides (81) were produced. Elimination via the N-oxide gave the corresponding thiete dioxide, whereas reduction by LiAlH4 yielded the thietane 82. 

Photolysis of thietan dioxides is a preparatively useful synthesis of cyclopropanes, particularly since stabilization of an cf-carbanion by a sulphonyl group allows wide latitude for manipulation. Thietan dioxide (101) gives (102) in 95% yield upon photolysis. Trimethylene sulphone gives trimethylene biradicals... 

Asymmetric induction and the synthesis of optically active thietane and thiete dioxides can be achieved via the basic strategy depicted above (equation 87), by using optically active enamine in the first (2 + 2) cycloaddition187 (equation 90). [Pg.449]

Cyclic carbonates of 1,3-propanediols yield thietanes when treated with thiocyanate ion and heated until carbon dioxide is evolved. Yields vary from 3 to 63%, the yield being greater for 3,3-disubstituted thietanes, as illustrated in the synthesis of the spirothietane, 44. Oxetanes are formed as byproducts in... 

The discovery by Stork and Borowitz and Opitz and Adolph that the addition of sulfenes (RCH=S02) to enamines gives good yields of 3-aminothietane-1,1-dioxides (e.g., 132) has been extensively exploited in the synthesis of a variety of thietane sulfone derivatives. Truce, Breiter, Abraham, and Norell at about the same time showed that sulfene can add to ketene acetals to give 3,3-dialkoxy substituted thietane 1,1-dioxides (e.g., 133). The sulfenes are generated by dehydrohalgenation of methanesulfonyl chlorides with triethylamine. [Attempts to add sulfines (e.g., PhCH=SO) to enamines to give thietane 1-oxides were not successful.1 Sulfene additions have been reviewed. ... 

The first synthesis of thiete 1,1-dioxide 248 was achieved by elimination of hydrogen chloride from 3-chlorothietane 1,1-dioxide. The overall synthesis from epichlorohydrin (chloromethyloxiran) has been improved in several details. 3-Bromothietane 1,1-dioxide ha.s been obtained by direct bromination of thietane hl-dioxide " and the 3-chloro-derivative has been obtained similarly. " ... 

Additions of the Michael type of nucleophiles to the carbon-carbon double bond of thiete 1,1-dioxides to give 3-substituted thietane 1,1-dioxides occur readily. The addition of hydrogen has been discussed in Section A. Nucleophiles include cyanide, the anion of nitroethane, the lithium salt of r-butyl o-tolyl sulfone, dimethylamine, cyclohexylamine, ethoxide, and hydrogen sulfide. The reaction is exemplified by the synthesis of 278. Additions to 3-chloro-2H-thiete 1,1-dioxide most likely proceed by an addition-elimination mechanism an example is shown for the addition of the anion of dimethylmalonate to give 279. The replacement of a 3-morpholinyl group by a 3-A methyl-A-phenylamino group in thiete 1,1-dioxide is another example of addition-elimination. An addition of ethoxide with elimination of p-nitrophenyl anion may occur with 268 (Ar = / -N02C6H4). " Addition of bromine via N-bromo-succinimide to the double bond of 4-phenyl-2H-thiete 1,1-dioxide occurs only in 1.5% yield. ... 

Mustela erminea). An efficient synthesis of thietans (74) has been achieved using P.T.C. and the thietans have been converted to their 1,1-dioxides (75) and then, by bromination and dehydrobromination, to the corresponding thiet 1,1-dioxides (76)... 

Alkylation of anions (88) and (89), followed by pyrolysis, provides novel methods of synthesis of carbonyl compounds and polycyclic hydrocarbons (including steroids), respectively. A synthesis of polycyclic hydrocarbons related to that based on the anion (89) involves alkylation of a benzocyclobutenyl-sulphonyl carbanion. Alkylation of a thietan 1,1-dioxide carbanion (90), followed by photolysis of the product, affords cyclopropanes. ... 

Formation.—The use of sulphenes in the synthesis of thietan 1,1-dioxides has been reviewed. -The formation of thietan 1,1-dioxides from enamines and sulphenes and the stereoselectivity of the reaction is discussed in Chapter 3, Section 2 (p. 140). When a mixture of cis- and /ro j-2-chloro-2,4,4-trimethyl-3-dialkylaminothietan 1,1-dioxides is treated with aqueous alkali, the c/j-isomer is converted into the thietan-3-one, leaving the pure rra/ij-isomer untouched. Cyclic a-amino-ketoximes can be converted in one step into... 

---