Anhydrides Anionic rearrangements

The differing nucleophilicity of acetate and trifluoroacetate anion determined the manner in which naphtho[l,8-/yt]-l,5-dithiocinc sulfoxide 127 rearranged on treatment with acetic and trifluoroacetic anhydrides. In both cases, the reaction proceeded through formation of a disulfonium dication 128, but the final products were different. When acetic anhydride was used, the reaction afforded the corresponding a-acetylsulfide 130, a normal product of the Pummerer rearrangement, while trifluoroacetic anhydride caused isomerization with formation of dithioacetal 132 (see Scheme 16) <1995HAC559>. 

Aminophenols from anilines, 35, 2 Anhydrides of aliphatic dibasic acids, Friedel-Crafts reaction with, 5, 5 Anion-assisted sigmatropic rearrangements, 43, 2 Anthracene homologs, synthesis of, 1, 6 Anti-Markownikoff hydration of alkenes, 13, 1... 

In acetonitrile, 237 and 238 are reduced in two one-electron steps through the anion-radical to the dianion in the presence of acetic anhydride, 238 forms a mixture of 1,2-diacetyl-1,2-dihydro-3-phenylpyrido[3,4-e]-as-tria-zine (239) and the 1,4-diacetyl-1,4-dihydro derivative (240). On heating of the kinetically controlled product, 239 rearranges to the thermodynamically more stable 240.37°... 

The intermediacy of phosphonoamidic-sulfonic anhydride (476) in the rearrangement of O-sulfonyl-N-phosphinoylhydroxylamine (477) with tert-butyla-mine was confirmed. The observed products, phosphonoamidate anion (478) and phosphonic diamide (479) correspond to attack of tert-butylamine at sulphur and phosphorus atoms of the anhydride (Scheme 110). ... 

In the first transformation, the carboxylic acid moieties are converted to the corresponding isocyanates employing a Curtius rearrangement. This transformation starts with the formation of mixed anhydride 33 which is subsequently attacked by the azide anion to give acyl azide 34. Then, acyl azide 34 rearranges with the formation of isocyanate 35 and nitrogen. As isocyanate 35 is unstable to hydrolysis... 

Tetra-t-butyldiphosphine oxide (21) has been prepared from the anion (22), and found to rearrange readily to the anhydride (23). The corresponding tetra-iso-... 

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