Methyl phenyl sulphone

The first study into the use of 6% sodium amalgam in refluxing ethanol for the reductive desulphurization of sulphones was reported116 in 1952. Methyl phenyl sulphone gave an... 

Other complex sulphones, e.g., 69 with several labile hydrogens, were studied54. Thus disulphonyl pinacols can be reduced (by four-electron cleavage) into pinacols in protic solution or decomposed by means of EGBs into benzil and methyl phenyl sulphone (R = Ph). With R = alkyl, other modes of cleavage by EGBs were found5 5- 57, especially the scission of the central C—C bond when 50% of the /i-ketosulphone could be isolated. 

Coulometric measurements demonstrated the formation of the thioether with an electricity consumption of one Faraday per mole. However, the thioether yield was only of the order of 50% and, in addition, the presence of sulphinate ion in the electrolysis solutions was shown by methylation with CH3I, when methyl phenyl sulphone was formed and determined. 

Electrochemical reduction of aryl sulphones in methanol leads to cleavage of one carbon-sulphur bond in a two-electron process. Alkyl aryl sulphones with an electron donating substituent in the aryl ring give the arenesulphinic acid and an alkane [68, 69]. Methyl phenyl sulphone and alkyl aryl sulphones with an electron withdrawing substituent in the aryl ring are cleaved to the substituted arene and the alkylsulphinic acid [70], see Scheme 5.2. In addition, a bulky orfAo-substituent such as tert.-butyl favours cleavage to the arene and alkanesulphinic acid [71]. 

Reaction of both methyl phenyl sulphone and diphenyl sulphone with potasium in liquid ammonia [24] leads to the formation of a dianion, which cleaves to give CfiHs, isolated as benzene. The initial electron transfer cannot be dissociative, as was the case for diethyl phenyl phosphate (p. 163), since the phenyl c-radical is not detected. The radical-anions from these sulphones have sufficiently long lifetime in liquid annmonia to allow reaction with a further electron. 

Deoxy-L-threose and -erythrose derivatives are available from ethyl 0-benzyl-L-lactate by chain elongation with the formyl anion eguivalent (21) and subseguent reduction of ketone (22) (Scheme 5). The anion of methyl phenyl sulphone has been added... 

The treatment of a dialdose derivative with lithiated methyl phenyl sulphone is discussed in chapter 11, and the preparation of a synthon of deazatunicamycin is covered in chapter 19. An improved synthesis of (6- C) aldohexoses from 1,2-Q-isopropvlidene-q-D-xylo-pentodialdo-l.4-furanose is included in chapter 2. The racemic synthesis of an aminosugar dialdose is mentioned in chapter 9. 

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