Isatin reaction with triphenylphosphine

The reaction of isatin with triphenylphosphine was believed to furnish indirrubin375, but a reinvestigation of this reaction has shown that the products formed are 3-... 

Reactions of Phosphines. - 1.2.1 Nucleophilic Attack at Carbon. Interest has continued in developing the synthetic applications of the 1 1 adducts of tertiary phosphines with dialkyl acetylenedicarboxylate esters. Protonation of the initial adduct from triphenylphosphine by phthalimide, followed by nucleophilic addition of the nitrogen of the resulting imido anion to the intermediate vinylphosphonium salt, has given the stabilised ylide system (189). ° Similar reactions with isatin and 3-chlorotetrahydrofuran-2,4-dione have given the yl-... 

Conversion of isatins into oxindoles can be achieved by catalytic reduction in acid, or by the Wolff-Kischner process.3-Substituted indoles result from Grignard addition at the ketone carbonyl, followed by lithium aluminium hydride reduction of the residual amide, then dehydration. The reaction of isatin with triphenylphosphine provides an easy synthesis of 3-(triphenylphosphorylidene)oxindole, a Wittig reagent. ... 

Trimethoxyphosphoranes (6) are among the products reported in new examples of reactions of the carbene intermediates (5). A re-investigation of the reaction of triphenylphosphine with isatin (7) has shown the previous reports to be incorrect and that the products are in fact the new phosphonium ylide (8) and isoindigo (9). ... 

Stable phosphorus ylides (50) and (51) have been prepared from the reaction of electron-deficient acetylenic esters, such as dialkyl acetylenedicarboxylates or alkyl propiolates and triphenylphosphine in the presence of 3-chlorotetrahyd-rofuran-2,4-dione (Scheme 10). These reactions are thought to proceed via vinylphosphonium salt intermediates which undergo Michael addition with the conjugate base of the CH-acid. Similar methodology has been used to prepare phosphonium ylide (52) from triphenylphosphine, isatin (indoline-2,3-dione) and dimethyl acetylenedicarboxylate. " ... 

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