Cyclic sulphones dioxides

Some studies have been made of the mass spectra of cyclic sulphones, sulphones of aromatic heterocyclesand benzothiazole S-dioxide. A direct analytical application does not appear to be known. 

It is intriguing to note that this reaction scheme for the reduction of a sulphone to a sulphide leads to the same reaction stoichiometry as proposed originally by Bordwell in 1951. Which of the three reaction pathways predominates will depend on the relative activation barriers for each process in any given molecule. All are known. Process (1) is preferred in somewhat strained cyclic sulphones (equations 22 and 24), process (2) occurs in the strained naphtho[l, 8-hc]thiete 1,1-dioxide, 2, cleavage of which leads to a reasonably stabilized aryl carbanion (equation 29) and process (3) occurs in unstrained sulphones, as outlined in equations (26) to (28). Examples of other nucleophiles attacking strained sulphones are in fact known. For instance, the very strained sulphone, 2, is cleaved by hydride from LAH, by methyllithium in ether at 20°, by sodium hydroxide in refluxing aqueous dioxane, and by lithium anilide in ether/THF at room temperature. In each case, the product resulted from a nucleophilic attack at the sulphonyl sulphur atom. Other examples of this process include the attack of hydroxide ion on highly strained thiirene S, S-dioxides , and an attack on norbornadienyl sulphone by methyllithium in ice-cold THF . ... 

Nitrogen analogues (5) of o-xylylenes are produced as transient intermediates in the flash pyrolysis of o-amino-benzyl alcohols (4). They do not undergo ring-closure to benzazetines but cyclize to acridines via dihydroacridines. Possibly the same type of imine methide is involved in the thermal and photochemical extrusion of sulphur dioxide from the cyclic sulphones (6), which in this case does give the benzazetine. ... 

Cyclic Sulphonates, Cyclic Sulphinates, and Related Systems.—A valuable new method of synthesizing 1,2-oxathiolan 2,2-dioxides and 1,2-oxathian... 

Quantitative M.O. models were used in a discussion of the photoelectron spectrum of thiiran 1,1-dioxide. As compared with dimethyl sulphone, all antibonding S—C cr-orbitals increase in energy and bonding S—C a-orbitals decrease in energy because of the relative compression of the S—C bonds in the cyclic sulphone. The chelotropic reactions of thiiran 1,1-dioxide have been compared with the formation of alkene-oxygen Tr-complexes. Activation parameters for the extrusion of sulphur dioxide from thiiran 1,1-dioxide have been obtained. ... 

Further data from the polarography and cyclic voltammetry in dimethylformamide are given in Table 5.1 for a series of overall two-electron processes leading to cleavage of a benzyl-heteroatom bond. The first electron transfer step is of the dissociative electron transfer type leading to a benzyl radical. This radical is reduced firrther, at the working potential, to the benzyl carbanion. The carbanion fi om benzyl chlorides, esters, ethers, sulphides, sulphones and quaternary ammonium salts can be trapped by carbon dioxide to form phenylacetic acid [2]. Reac-... 

Homolysis of the S-acyl bond is responsible for formation of phenylthio-cyclohexane and 3-phenylthiocyclohexene from. SiS -diphenyl dithiocarbonate by irradiation in cyclohexene.117 A cyclic mechanism, however, has been proposed to account for the photodecomposition of certain carbohydrate dithiobisthio-formates.118 On irradiation, 0-ethyl thioacetate is converted into cis- and / 5-2,3-diethoxybut-2-ene, together with small amounts of 2,3-diethoxybut-l-ene, 2,3-diethoxybuta-1,3-diene, and 1-ethoxyethane-l-thiol.119 121 Free sulphur was trapped by reaction with 1,2-dimethyIenecyclohexane. Details of the photoelimination of sulphur dioxide from D-glucofuranosyl phenyl sulphone acetates have been published.180 An efficient synthesis of another 1,8-bridged naphthalene... 

Like their 1-alkenyl analogues, 2-alkynylcysteine S -oxides and SS-dioxides in the presence of base undergo an internal addition of the amino-function to the triple bond to yield cyclic sulphoxides and sulphones. ... 

The use of crown polyethers to solubilize potassium permanganate in benzene has been reported. In a study of the oxidation of alkyl toluene-/ -sulphonates with DMSO-sodium bicarbonate, the elements of carbon dioxide are retained in the product (86) as a cyclic carbonate (Scheme 170), inferring that, for this substrate, bicarbonate ion is a more effective nucleophile than DMSO this leads to a revision of the mechanism of such oxidations to that shown in Scheme 170. 

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... 

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