Sulfones, epoxy preparation

Desulfurization of fl, a-epoxy sulfones 239 prepared from allylic sulfones 238 and m-chloroperbenzoic acid with sodium amalgam leads to the formation of allyl alcohols (240) in good yields (equation 144)138. Allyl alcohols prepared by this method are listed in Table 16. 

The epoxy sulfones were prepared by exhaustive peracid oxidation of the corresponding alkene sulfides. These were generated by ring expansion of cyclic 1-methyl-2-vinyl sulfonium salts 1 via 2,3-sigmatropic rearrangement of the methanides. From the five-membered sulfonium ylide la, (Z)- and ( )-thiacyclooct-4-enes 2 were obtained as an 85 15 mixture. Their chromatographic separation turned out not to be feasible due to concomitant EjZ isomerization on the silica gel column. Since the separation of these epoxy sulfone mixtures obtained by exhaustive oxidation also proved unsuccessful, it was found expedient to first oxidize the mixture of sulfides to an alkene sulfone mixture ( )-3, which could be separated and eventually epoxidized into epoxides cis- and trans-4 and cis- and trans-5. 

Watt and coworkers139 prepared the a-azidoaldehydes (242) by nucleophilic ring opening with sulfinate ion expulsion of a, /(-epoxy sulfones 241 with sodium azide in DMF... 

This procedure describes a recently reported extension of this reagent and catalyst system for the preparation of epoxysulfones (1) and exemplifies this with the synthesis of multifunctional epoxy sulfone (2) in good ee. ... 

Diaminodiphenyl sulfone (DDS) cured tetraglycidyl-4,4 -diaminodiphenylmethane (TGDDM) epoxies are the mpst common composite matrices utilized in high performance fibrous composites prepared from prepregs. The structures of the unreacted TGDDM epoxide and DDS monomers are illustrated in Fig. 3. The TGDDM epoxide monomer is a liquid at 23 °C, whereas the DDS monomer is a crystalline... 

The epoxy-Ramberg-Backlund reaction (ERBR) has been used for the conversion of a,/3-epoxy sulfones into a range of mono-, di-, and tri-substituted allylic alcohols.34 Modification of this method has permitted the preparation of enantio-enriched allylic alcohols following the diastereoselective epoxidation of enantio-enriched vinyl sulfones that were accessed efficiently from the chiral pool. 

Spirocyclization of an epoxy sulfone,J A short synthesis of nitramide (3) involves as the key step the reaction of the epoxy sulfone 1 with 2 equiv. of BuLi in THF/HMPA (9 1) to form the spirocycle 2 (73% yield). Both the sulfone and sulfonamide groups are cleaved by freshly prepared sodium amalgam (7,326-327). 

Epoxidation of vinyl sulfones is the most common procedure for the preparation of a,/l-epoxy sulfones514. Organolithium compounds derived from a,/8-epoxy sulfones 336... 

Racemic epoxy sulfone derivatives are easily prepared from al-lyl ethers by reaction with sodium p-toluenesulfinate in the presence of iodine followed by treatment with triethylamine, separation of E- and Z-isomers, and epoxidation with t-BuOOH and n-BuLi in THE (eq 3). ... 

A novel tandem process has been reported " for the preparation of allylic amines, ethers, and sulfides from a-bromo-a, jS-unsaturated sulfones. The process is believed to proceed via an initial conjugate addition followed by proton exchange and Ramberg-Backlund rearrangement (see Scheme 75). A new variant of the Ramberg-Backlund reaction has been described in which a, /f-epoxy sulfones (319), on treatment with base, are converted into a range of mono-, di-, and tri-substituted allylic alcohols (320). 

Treatment of the epoxy sulfones obtained thus with MgBr2 produces a-bromo ketones or a-bromo al-dehyde. This conversion can be applied to stereoselective preparations of a-bromo methyl ketones from cyclohexanone derivatives. Thus, treatment of 17-P-hydroxy-5-a-androstan-3-one (134) with 1-chloroethyl phenyl sulfone provides an epoxy sulfone (135), which is cleaved by MgBr2 to give a 99 1 mixture of 3-acetyl-3-bromoandrostanes (136 and 137 equation 33), whereas similar treatment of 17-p-hydroxy-5-B-androstan-3-one (138) gives a 4 96 mixture of 3-acetyl-3-bromoandrostanes (139 and 140 equation 34). These facts may reflect the steric course of the initial attack of the a-sulfonyl carbanion on the carbonyl face. 

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