Sulfones cyclic

Diazoalkanes add to the carbon-carbon double bonds of 2,3-diphenylthiirene 1-oxide and 1,1-dioxide. The adducts lose SO or SO2 to give pyrazoles and related compounds (Scheme 103) (80CB1632). Mesoionic oxazolones (75CLH53), 4-methyl-5-phenyl-l,2-dithiolene-3-thione (80JOU395) and pyrylium betaines (72JOC3838) react similarly via intermediate adducts (Scheme 104). Enamines (Scheme 96) and ynamines add to the double bond of 2,3-diarylthiirene 1,1-dioxides to give acyclic and cyclic sulfones by a thermal. 

Alkyl sulfonyl chlorides, having an a-hydrogen atom, react with enamines derived from aldehydes and cyclic ketones in the presence of triethylamine to give cyclic sulfones. Thus the enamine (22) gave the four-membered cyclic aminosulfone (143) on reaction with methanesulfonyl chloride (95). 

In a similar manner the enamine (113) reacted with methanesulfonyl chloride (96) to give the cyclic sulfone (144). 

The formation of the same four-membered ring aminosulfone (145) from the enamine (22) and cyclohexanesulfonyl chloride in 72% yield and from N-(cyclohexylidenemethyl)pyrrolidine (146) and 2-propanesulfonyl chloride in 77 % yield proves the constitution of these cyclic sulfones (97). 

The dienamine (148) can react in two ways with methane sulfonyl chloride. In one a 1,4 Diels-Alder-type addition gives 149 in the other way the initially formed product reacts further to give the bis-cyclic sulfone (150) (102,103). 

Allylsulfonyl chloride and enamines furnished the sulfonyl enamines or cyclic sulfones 704), and alkyldisulfonyl chlorides gave 1 2 adducts or bicyclic products with morpholinocyclohexene. 

Furlei and coworkers44 studied the negative ion mass spectra of several cyclic sulfones (82-98) upon dissociative electron capture and concluded that the negative molecular ions were notably stabilized by the introduction of electron-withdrawing substituents and/or unsaturation. Some difference was found in the negative ion mass spectra of configurational isomers (85 vs. 86 and 87 vs. 88) in contrast to the situation in their positive ion spectra. A strong S02 ion (m/z 64) was observed also for all the compounds studied. 

These methods use sulfur dioxide as a building block, generally for cyclic sulfones. However, since several variations allow the preparation of open-chain sulfones too (Section III.D), several selected examples will be presented here. 

The following chapter constitutes a walk on the trail of cyclic sulfones and sulfoxides, an intriguing and interesting class of compounds, that displays a variety of novel and unique properties, particularly when of small ring size. 

In view of the fact that the chemistry of ring compounds has played a considerable role in the development of modern organic chemistry, the following question is definitely relevant Do cyclic sulfones and sulfoxides envisioned as a particular distinct category within this class of compounds contribute uniquely—in their own right—to the understanding of the characteristics and chemistry of the sulfone and sulfoxide functionalities and their role in organic chemistry ... 

Similarly, only selected cyclic systems containing more than one sulfoxide or sulfone groups have been included and discussed here, primarily in the thietane (i.e. 1,2- and 1,3-dithietanes) and thiane (i.e. 1,2-, 1,3- and 1,4-dithianes) series. The criterion for the inclusion of these multifunctional heterocycles was their contribution to the understanding of the physical properties and chemical reactivity of cyclic sulfones and sulfoxides, and the effects of these groups on either their immediate vicinity or on the behavior of the whole molecule. 

The field of cyclic sulfones and sulfoxides also provides a challenge for further investigations. Four possible directions for future research are as follows ... 

Expansions of cyclic sulfones to cyclic sulfinates are known124, and a similar mechanistic pathway of the expansion of the three-membered ring to a four-membered ring has been suggested for the photolytic fragmentation of the 2,3-diphenylthiirene oxide 18a22. 

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