Smiles rearrangement rearrangement

Heteroatom Heteroatom Aromatic Rearrangements (Smiles Rearrangement) The... 

Thiophene, 2-methyl-5-(mesitylsulfonyl)-Truce-Smiles rearrangement, 4, 825 Thiophene, 2-methyl-3-nitro-acidity, 4, 799... 

In the Schmidt reaction of fluonnated dicarboxyhc acids, the appropnate amides can be obtained in fairly good yield [48] Complications arise from possible cychzation if the fluorine atom is in the 8 position relative to the newly formed amino group [/] Fluonnated aromatic ethers, upon heating in dimethylformamide, undergo Smiles rearrangement to give diarylamines [49, 50] (equation 11)... 

Smiles rearrangement was observed also in base-catalyzed cyclization of 2-hydroxy-2 -nitrodiphenylsulfones leading to low yields (about 5%) of phenoxathiine 10,10-dioxides (34JCS422, 56JA5357). However, this type of compounds can be easily prepared by other methods (05CB1411, 06CB1340). 

Use of some pyridinium oxides in this reaction was also described and the formed azaphenoxathiin /V-oxides can be easily converted to their mother heterocycles (80JHC989, 87JHC211). When 3-chloro-4-nitropyridine 1-oxide (271) was used, small amounts of products of Smiles rearrangement were... 

Chloro-5-nitrobenzaldehyde, -acetophenone, or -benzophenone derivatives treated with 2-aminothiophenol under alkaline conditions provided good yields of the corresponding dibenzo[(3,/][l,4]thiepins. Similar treatment of 2-chloro-3,5-dinitrobenzophenone (318) provided 58% of dibenzo[(3,/][l,4]thiepin 321 and 20% of phenothiazine 323. Its formation can be easily explain by the Smiles rearrangement of the initially formed intermediate 320 into diphenylamine derivative 322, followed by denitrocyclization reaction leading to the corresponding product of denitrocyclization 323 (Scheme 49). When the reaction was done in pyridine, only this product was isolated in 50% yield (57JCS3818). 

The Smiles rearrangement of sulfones 352 led to intermediates 353 the final ring closure was done in glacial acetic acid to provide the corresponding products of denitrocyclization 354 in 66% yield (Scheme 54) (72JHC699). 

Intramolecular cyclization can yield fluorinated phenoxazines by a Smiles rearrangement (86IZV1855) and 2,3-dihydro-l,4-benzodioxins by a base-induced reaction [81JFC(18)483]. 

Both cis- and rrans-l-arylsulfonyl-2-arylsulfenyl propenes (56) underwent a Smiles rearrangement under electron impact at 20 and 70 eV and formed a diarylsulfide ion [M — 104]+ (equation 27a)39 through a process where a bond between the R C H group and the sulfide sulfur is formed and a rearomatization occurs by a loss of the neutral thiirene dioxide or a simultaneous expulsion of SOz and propyne. The ion m/z 148 was also obtained from all of the sulfonyl-sulfides, 56 (equation 27b) and here the loss of R2 seemed to be related to the bond strength39. In addition to the above compounds 56 exhibited some simple cleavages before and after sulfone-sulfinate rearrangements. 

A Smiles rearrangement (equation 28) was also responsible for the secondary loss of SOz in the El induced fragmentation of 2-(p-chlorophenoxymethyl)-3-arylsulfonylmethyl-5-chlorobenzo(h)thiophenes (59) but not in their 3-alkylsulfonylmethyl derivatives33. In the latter, the loss of RS02 from the molecular ions and those of RS02 and RSOH from the [M — C1C6H40] + ions are the predominant routes of fragmentation. 

Nucleophilic substitutions of halogen by the addition-elimination pathway in electron-deficient six-membered hetarenes by sulfinate anions under formation of sulfones have been described earlier120. The corresponding electron-poor arenes behave similarly121 (equation 30). A special type of this reaction represents the inverse Smiles rearrangement in equation 31122. 

Coats and Gibson250 have reported that sulfmic acids obtained from the rearrangement of o-hydroxy sulfones can be reconverted to the original sulfones. This reaction, which has been designated as the reverse Smiles rearrangement, took place readily when the sulfinic... 

In reducing media, a synthetically useful variation of the Smiles rearrangement, which leads to the formation of fused ring systems, has been observed (equation 77)251. In this reaction, rearrangement is followed by displacement of the sulfinate anion by a nucleophilic o -substituent. 

---