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 (13) with (Z)-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
Anodic fluorination of various N-acetyl-3-substituted indole derivatives was successfully carried out in Et(4)NF-4HF/MeCN to provide the corresponding trans-2,3-difluoro-2,3-dihydroindoles exclusively or selectively. Treatment of difluorinated products with a base provided monofluoroindole derivatives or monofluoroindoline derivative depending on the substituents at the 3-position. (C) 2010 Elsevier Ltd. All rights reserved.
First Total Synthesis of Dragmacidin A via Indolylglycines
The first totalsynthesis of dragmacidin A has been accomplished using condensation of two indolylglycines followed by cyclization and reduction. The general and practical method for synthesis of indolylglycines via Wittig reaction, azide addition, and reduction from indolin-3-ones is also described.