Smiles-type rearrangement

Compounds 45 exhibit, in addition to sulfone-sulfinate rearrangements " ", alkyl sulfone cleavages , intramolecular Smiles-type rearrangements and extrusion of SOj , an exceptional mode of remote group interaction which leads to the loss of... 

Pyridyl-2-hydroxybenzo[b]furans have been obtained by an unexpected Truce-Smiles type rearrangement of 2-(2 -pyridyloxy)phenylacetic esters 111. Yields of these conversions were not recorded <00TL4541>. 

The Smiles-type rearrangement of phenyl o-tolyl sulfone [222] has been shown to proceed via an addition-elimination pathway by isolation of the tricyclic intermediate. Both sites of deprotonation and addition are controlled by the sulfonyl group with contrapolarization at the second stage. 

Traditional routes to phenoxazines include the thermolysis of 2-aminophenol and catechol, the latter acting as an acid catalyst, or catechol and ammonia. Phenothiazines are prepared similarly by heating diphenylamines with sulfur (Scheme 10) (B-78MI22701). 2-Hydroxy- (or mercapto-) 2, 4 -dini-trodiphenylamines cyclize to phenoxazines (or phenothiazines) in base by elimination of nitrous acid. This reaction is complicated by Smiles-type rearrangement so that mixtures of isomeric products are obtained (Scheme 11). 

Smiles-type rearrangement followed by cyclization has been described in the formation of thieno[2,3-h][l,6]-naphthryridine skeleton (43) from 2-(3-cyanopropylthio)pyridine-3-carbonitrile (44) (Scheme 31) <95H(41)1307>. 

Reaction of (69) with the tetramethylene diamine at temperatures below 50 °C affords the azepinopyridine derivative (70). A complex reaction mechanism has been proposed, involving the intermediate formation of the pyridone (71), which undergoes a Smiles type rearrangement to give the final product <95J1IC477>. 

The Smiles-type rearrangement in acyclic systems was recorded in the already discussed work of C.R. Johnson and coworkers [78] (Scheme 53 and the relevant text). Reaction of an anion generated from dithiocarbamate 201 (Scheme 60) with propionaldehyde afforded adducts 202 (95% yield). Treatment of this product with NaH in THF gave thiirane 205 in 78% yield as a mixture of cis/trans isomers. 

The reagent ratio 1 2 leads to a disubstituted product, which reacts with aminoethanol in an alkaline solvent to give 5,8-bis(vinylthio)-6,7-difluoro-2,3-dihydro-l,4-benzoxazine 164 along with other products (92ZOR1463) (Scheme 154). The formation of compound 165 is possibly explained by a Smiles type rearrangement. 

The ratio between the isomeric phenoxazine products suggests that the main route of cyclization is a direct attack of the second nucleophilic center at the ortho-carbon atom of the aromatic ring an alternative route is a Smiles type rearrangement (70M9). Therefore, the following route of cyclization was proposed (Scheme 171). 

Simmons-Smith cyclopropanation, 456 Simmons-Smith reaction, 455 six-centered transition state, 264 Smiles-type rearrangement, 7 SOCI2, 19, 159 sodium azide, 365, 375 sodium borohydride, 416 sodium hexamethyldisilazide, 290 sodium hydride, 372, 375. 383 sodium in liquid ammonia, 440 sodium iodide, 379 sodium phenylselenide, 458 sodium trifluoroethoxide, 447 solid phase synthesis, 25 Sonogashira conditions, 409 Sonogashira coupling, 411 spartadienedione, 144 spontaneous csdodimerization, 23 S-shaped and C-shaped diastereomers, 83 stainless steel reactor, 283... 

In a complex series of transformations, reaction of the diene (36) with 1,4-diaminobutane results in the formation of the bicyclic pyrido[l,2-a][l,3]diazepine (37) in what is a formal insertion of a Cl fragment into the diamine <95JHC477>. Initial nucleophilic replacement of the thiomethyl group by the diamine and subsequent cyclization is followed by a Smiles-type rearrangement, then sequential ring-opening and ring-closure transformations. 

An unexpected Truce-Smiles type rearrangement of the acid ester 53 in the presence of KH or NaH in THF afforded the benzofuranones 55 via the intermediate 54. ... 

New synthetic methods for benzodiazepine synthesis involving Ugi-type multicomponent/post-Ugi cyclization reactions continue to be of interest. Ugi reactions of indole-2-carboxaldehydes, isocyanides, amines, and 2-iodobenzoic acid derivatives led to intermediates which, with copper(I) catalysis, underwent intramolecular indole N-arylation to produce indolo-fused benzodiazepinones, such as 134 (13CC2894). 2-Azido-benzaldehyde, isocyanides, propargylamines, and nitrophenols underwent Ugi-type reaction, Smiles-type rearrangement, and intramolecular azide-alkyne cyclization to afford triazolo-fused benzodiazepinones such as 135... 

An intramolecular electron-transfer/radical anion mechanism has been advocated for the Truce-Smiles-type rearrangement of t-butyl aryl sulphones by Bu"Li at —78 C, orf Ao-lithiation of the aryl moiety being followed by migration of the t-butyl group to the metallated site. Other methods of C—S bond cleavage that are covered in recent papers include photolysis and electrochemical reduction, ... 

Potassium hydroxide 2-Acyl-3-hydroxyquinolines via Smiles-type rearrangement 452. (C0CH3)2... 

Gonzalez JP, Edgar M, Elsegood MRJ, Weaver GW (2011) Synthesis of Huorinated fused benzofurans and benzothiophenes smiles-type rearrangement and cyclization of perfluoro(het)aryl ethers and sulfides. Org Biomol Chem 9(7) 2294-2305... 

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