(Z)-stereoselective Wittig olefination of 2-oxygenated indol-3(2H)-ones

Abstract

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. These isomerizations are also described.