Sulphones addition reactions

Given the above possible reaction mechanism, it is then intriguing to speculate that another approach to the same stereoselective reduction of a vinyl sulphone could be achieved by the use of a suitably sterically hindered organosilane, as outlined in equation (64). Such a reaction would provide an interesting test for the stereoelectronics of a conjugate addition reaction by a second-row heteroatom to a vinyl sulphone. 

Sulphones - see also Acetoxysulphones, /1-Acyloxysulphones, a-Alkoxysulphones, a-Aminosulphones, Azidosulphones, Azosulphones, Azoxysulphones, co-Cyanosulphones, Dialkoxysulphones, a-Diazosulphones, Disulphones, Episulphones, Epoxysulphones, a-Halosulphones, Hydroxysulphones, / -Iminosulphones, Ketosulphones, a-Lithiosulphones, a-Nitrosulphones, /1-Oxosulphones, Poly(olefin suphonejs, Polysulphones, y-Siloxysulphones, Tetrahalosulphones, Trisulphones addition reactions of 642-649, 774-809 alkadienyl - see Alkadienyl sulphones alkenyl - see Alkenyl sulphones alkyl aryl - see Alkyl aryl sulphones alkylthiomethyl - see Alkylthiomethyl sulphones... 

Organic hydroperoxides have also been used for the oxidation of sulphoxides to sulphones. The reaction in neutral solution occurs at a reasonable rate in the presence of transition metal ion catalysts such as vanadium, molybdenum and titanium - , but does not occur in aqueous media . The usual reaction conditions involve dissolution of the sulphoxide in alcohols, ethers or benzene followed by dropwise addition of the hydroperoxide at temperatures of 50-80 °C. By this method dimethyl sulphoxide and methyl phenyl sulphoxide have been oxidized to the corresponding sulphone in greater than 90% yields . A similar method for the oxidation of sulphoxides has been patented . Unsaturated sulphoxides are oxidized to the sulphone without affecting the carbon-carbon double bonds. A further patent has also been obtained for the reaction of dimethyl sulphoxide with an organic hydroperoxide as shown in equation (19). 

However, in an intriguing reaction promoted by the para-nitro groups of the aryl-sulphone (1) (Scheme 6.25), the initial Michael adduct derived from acrylic esters produces the diarylpropanoic esters (2), together with the diesters (3) (from methyl or ethyl acrylate) [39]. A similar addition-rearrangement reaction has been observed with l-aryl-2-(4-nitrobenzenesulphonyl)ethanones [40]. Additionally, reaction of the sulphonylethanone with two equivalents of the acrylic ester produces a 4-hydroxy-1,4-diarylcyclohexane-1,3-dicarboxylate. 

PAULMIER Selenium Reagents Intermediates in Organic Synthesis PERLMUTTER Conjugate Addition Reactions in Organic Synthesis SIMPKINS Sulphones in Organic Synthesis WONG WHITESIDES Enzymes in Synthetic Organic Chemistry... 

P.L.Fuchs and T.F.Braish, Multiply Convergent Syntheses via Conjugate-addition Reactions to Cycloalkenyl Sulphones, ... 

McKILLOP Advanced Problems in Organic Reaction Mechanisms PERLMUTTER Conjugate Addition Reactions in Organic Synthesis SESSLER WEGHORN Expanded, Contracted Isomeric Porphyrins SIMPKINS Sulphones In Organic Synthesis TANG LEVY Chemistry of C-Glycosides... 

A few instances have been noted of allyhc compounds bearing an electron-attracting substituent undergoing addition reactions with amines. These cases appear to involve shift of the double bond from the 8,y- to the a, 8-position prior to reaction. For example, benzyl allyl sulphone and piperidine react to give benzyl 8-piperidinopropyl sulphone (reaction 81)i i. Allyl cyanide similarly reacts with am-... 

Addition reactions of vinyl sulphones (Diels-Alder addition, [2 -i- 2]-photocycloaddition, and conventional functionalization processes, e.g. IN 3 2-azido-l-iodoalkyl sulphones °°) and substitution reactions of / -halogeno-vinyl sulphones have been reported. A point of interest in the cycloaddition study is the effect of ( )-(Z) equilibration in hindering the participation of simple vinyl sulphones in photocycloaddition reactions. Elimination of SO2 has been observed in the photolysis of 3-oxo-alk-l-enyl sulphones in benzene, giving radicals which attack the solvent. ... 

In contradiction to other reports claiming a cycloaddition mechanism, a sulphinylamine gives an cf-amino-sulphonic acid R NHCHR S03H with aldehydes through successive hydrolysis and then condensation and bisulphite-addition reactions. ... 

At high temperatures the image of photodegradation changes completely because additional reactions are involved in the thermal degradation of a polymer [1319]. Many papers have been devoted to the study of photothermal degradation of polyethylene [148,1289], polypropylene [822], poly(ethylene-co-carbon monoxide) [871, 917], polyacrylates and polymethacrylates [821, 829], poly(acrylate-co-methacrylate) [828, 831], poly(vinyl chloride) [311, 702, 768, 891,1097,1319,1792] polystyrene [1491], natural rubber [14] and poly(ether sulphone) [1265]. 

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