The Wittig reaction of 1 -acetyl-2-methoxy-(1) and 1 -acetyl-2-hydroxyindol-3(2H)-one (2) with stabilized and semistabilized ylides gave predominantly 3-alkylidenedihydroindoles (4), ( 7 ) , and (1 3) with (2) -stereochemistry. When the Wittig reaction was carried out under more drastic conditions, the Wittig products ( 4) and ( 7) isomerized to afford 3-alkylindoles ( 5) and the indol-2-one (8), respectively. These isomerizations are also described.The Wittig reaction is a powerful method for the stereocontrolled construction of carbon-carbon bonds.' It has recently been reported that a-oxygenated ketones react with stabilized ylides to give predominantly allylic oxygenated (E)alkenes,2 while with nonstabilized ylides mainly (Z)-alkenes are ~b t a i n e d . ~Previously we briefly reported the reaction of stabilized ylides with the 2-methoxyindolone (1) as the aoxygenated ketone which was employed as a key step in a synthesis of the carbazole alkaloid hyella~ole.~ We now report the stereoselective Wittig reaction of the 2-oxygenated indolones (1) and (2) with stabilized and semistabilized ylides to give preferentially (2)-2-oxygenated 3-alkylidenedihydroindoles (4), (7), and (13), and their thermal isomerization to the indoles (5) and the indolone (8).
173ChemInform Abstract The hydroxyindolinones (IIa) and (IIb) react with acetic anhydride to give the corresponding acetates (Ia) and (Ib) and with methyl iodide to give the ether (IIIa). Condensation of the compounds (IIa) and (IIc) with phenylenediamine (IV) yields the quinoxalines (Va) and (Vc). The products (VIIa), (VIIIa), (VIIb), (VIIc), and (IXc) are obtained by the Wittig reaction of (IIa) -(IIc) with the phosphorane (VI). The bishydroxyindoline (X) is acetylated, forming the products (XI) and (XII), whereas the reaction of (X) with (VI) yields the lactone (XIII). (1H-, 13C-NMR-data).
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