Synthesis of 3-Acyloxyindolenines by TiCl3-Mediated Reductive Cyclization of 2-(ortho-Nitroaryl)-Substituted Enol
Dina V Boyarskaya1, Alberto Ongaro1, Cyril Piemontesi1
1Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, Lausanne 1015, Switzerland.
Abstract:
In the presence of TiCl3, the reductive cyclization of tetrasubstituted enol esters bearing a 2-(ortho-nitroaryl) substituent affords 3-acyloxy-2,3-disubstituted indolenines in good yields. A domino process involving the partial reduction of nitro to a nitroso group followed by 5-center-6π-electrocyclization, 1,2-acyloxy migration, and the further reduction of the resulting nitrone intermediate accounts for the reaction outcome. The so-obtained indolenines are converted smoothly to 2,2-disubstituted oxindoles via a sequence of saponification and semipinacol rearrangement.
More Related Videos
06:34Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS
Published on: June 20, 2014
06:31Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators
Published on: November 27, 2015
Related Concept Videos
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview
Intramolecular Claisen Condensation of Dicarboxylic Esters: Dieckmann Cyclization
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Nitrosation of Enols
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
