Alkylation of sulfones

WFor a review, see Magnus Tetrahedron 1977,33, 2019-2045, pp. 2022-2025. For alkylation of sulfones containing the F3CSO2 group, see Hendrickson Sternbach Bair Acc. Chem. Res. 1977, 10, 306-312. 

Alkylation of sulfones 0-95 Alkylation of sulfones 0-99 Reaction of halo sulfones with boranes... 

Sulfoxides and sulfones can be prepared on cross-linked polystyrene by oxidation of thioethers. The most commonly used reagent for this purpose is MCPBA in DCM [8,12,32,57,80-82] or dioxane [50,83] (Table 8.6), but other oxidants such as H2O2 in acetic acid [34], oxone (Entry 7, Table 8.6), or oxaziridines [84] have also been used. PEG-bound thioethers have been converted into sulfones by oxidation with MCPBA in DCM [52,54] or with Os04/NMO [85], The oxidation of thioethers to sulfoxides requires careful control of the reaction conditions to prevent the formation of sulfones. Sulfones have also been prepared by S-alkylation of polystyrene-bound sulfi-nates (Entries 8 and 9, Table 8.6), by a-alkylation of sulfones (BuLi, THF, alkyl halide [86]), and by addition of sulfinyl radicals to resin-bound alkenes or alkynes (Entry 11, Table 8.6). 

Terminal aikenes. /8-Silyl sulfones on treatment with fluoride ion undergo elimination to the corresponding alkene. This reaction, coupled with a -alkylation of sulfones, is useful for synthesis of terminal olefins and 1,3-dienes. 

The alkylation of sulfones has played an important role in this development. Most of this work has been performed with aryl sulfones, and in only rare cases have triflones (RS02CF3) or dialkyl sulfones been employed. ... 

Alkylations of sulfones with secondary alkyl halides have been described only rarely.43 .438 They usually proceed with modest yields and require both long reaction times and the presence of HMPA (Scheme 106, entry b). The presence of an aryl group on the carbanionic center softens this site however, and usually favors the alkylation reaction.443.46i,463... 

Cyclization via n-allylpalladium complexes. Trost and Verhoeven have reported several cyclizations involving a-alkylation of sulfones by means of ir-allylpalladium complexes (equations I and II). 

Alkylation of sulfone 115 with 116 was carried out with two molar equivalents each of 115 and sodium hydride to provide adduct 117 as a 1 1 mixture of diestereomers at C-1 in 82% yield based on 116. Interestingly, the C-5 nitro... 

Desuifonylation. Sulfones are useful in synthesis because alkylation a to the SOaR group is accomplished readily and the sulfone group can be eliminated after the alkylation by various reagents, particularly sodium amalgam (6%). Examples of the synthesis of vinylic halides by alkylation of sulfones with 1,3-dichloropropene and 2,3-dichloropropene are formulated, together with products of hydrolysis (aldehydes and ketones). ... 

Robin and Huet have reported a general method for the synthesis of 8-lactones as weU as lactones with several ring sizes via oxidation of the corresponding lactol [87] (Scheme 43). Alkylation of sulfone 211 with bromoacetaldehyde dimethyl acetal, cleavage of the silyl ether, and treatment with acetic acid afforded lactol 212. Oxidation of lactol 212 with PCC furnished the corresponding saturated 8-lactone 213, which underwent elimination of sulfinic acid in the presence of DBU to provide lactone 214. 

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