Bicyclic sulfone

A procedure for a synthesis of dienyl sulfoxides (232 and 233) involves ring opening of dihydrothiophene 1,1-dioxide (231) by two molar equivalents of Grignard reagent (equation 141)136. The yields are usually in the 20-66% range. Similarly, treatment of the bicyclic sulfones 234, with 2 equivalents of phenylmagnesium bromide, produced a mixture of 1,4-dienylic sulfoxides (equation 142)136. 

FVP of the aza-bicyclic sulfone 236 at 700°C and 8xl0 2mbar resulted in 3//-pyrrolizin-3-one 237 <2004TL3889>. At same temperature and lower pressure, that is, 4 x 10-2 mbar, the same sulfone affords a mixture of 237 and vinyl pyrrole 238 in 44% and 27% yield, respectively. The latter was the only product obtained when the thermolysis of 236 was performed in a sealed tube in sulfolane. This result and others led Pinho e Melo et al. <2005JOC6629> to suggest the plausible eight-step mechanism shown in Scheme 61. 

The DPM rearrangement of 4H-thiopyran-l,1-dioxide 39 takes place under both direct and triplet-sensitized irradiation, to yield bicyclic sulfones 40 and 41 (Scheme 4.17). The singlet excited state of39 leads to only the syn-form 41. Although... 

Compound A was synthesized in 1969, but was found not to be identical with sesquifenchene. A structure was proposed, B, which was synthesized in 1971—but this compound too had differ-t properties from those of natural sesquifenchene A third structure was proposed, C, and it was de from a bicyclic sulfone. 

A very specific yet interesting epoxidation method for bicyclic a,(3-unsaturated sulfones has been reported <07SL1948>. Reaction of bicyclic sulfone 10 with A-methylmorpholine N-oxide (NMO) provides the epoxide product in generally good yields. Other amine oxides such as trimethylamine A-oxide work in this reaction, however non-strained sulfones do not react even with heating. 

Palladium-catalyzed cycloisomerization of lactone 276 produced the tricyclic lactone 277 (Scheme 31). The lactone was saponified and the generated acid was decarboxylated to the bicyclic sulfone 278. Oxidation of the primary alcohol to the acid with Jones reagent was followed by esterification yielding 279. Now, the... 

Cadogan et al. have prepared epoxide 14 from bicyclic sulfone 13. Acid-catalyzed ring opening gives a mixture of exo,exo- and exo,endo-htov[io yAnns (Scheme 6) <1996J(P2)2309>. 

Aitken et al. have also oxidized bicyclic sulfone 13 (performic acid 39% yield). Flash vacuum pyrolysis of epoxide 14 (580 °C) gives a 55% yield of 4,5-dihydrooxepine, identified by comparison of its H and NMR data with the literature values. The dihydrooxepine presumably results from initial extrusion of SO2 to give t-2,3-divinyloxirane, which then undergoes a Cope rearrangement (Scheme 7) <1999J(P1)605>. 

In the synthesis of an ionophore antibiotic, a bicyclic sulfone made by oxidation of the corresponding sulfide with PhSeSePh/H202 to avoid double bond oxidation was coupled with an allylic bromide in 97% yield and high stereoselectivity. The sulfonyl group was finally eliminated in basic medium to create a trans-dxene (Scheme 66). 

The methylation of the cyclohexenyl sulfone shown in Scheme 116 (entry a) proved most interesting in that equatorial attack predominates. Such a result is quite surprising since a twist boat conformation leading to (7 Scheme 116, entry a) would be required as an initial product in order to maintain orbital overlap. The stereochemistry resulting from the methylation of the bicyclic sulfones (9) and (10) is also most unusual (Scheme 116, entries b and c). Not only is the stereochemistry of the alkylation inde-... 

Anionic Sodium bis(2-ethylhexyl sulfosuccinate) [AOT] Bicyclic sulfonates Di(2-ethylhexyl) phosphoric acid [DEHPA] Di(2-ethylhexyl) phosphorothioic acid [DEPTA] Di(oleyl) phosphoric acid [DOLPA] Di(tridecyl) phosphoric acid Sodium dodecylbenzenesulfonate [SDBS]/1-butanol [4, and references therein] [5] [6,7] [8] [9,10] [11] [12]... 

To dimethylbutadiene TCTD adds only as a dienophile to give the bicyclic sulfone (4) (eq 5)4... 

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