Synthesis of (2-(Quinolin-2-yl)phenyl)carbamates by a One-Pot Friedel-Crafts Reaction/Oxidative Umpolung Aza-Grob
Dong Xie1,2, Xin Xu2, Sihui Long1
1Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, 216 1st Road Optics Valley, East Lake New Technology Development District, Wuhan, Hubei 430205, P. R. China.
Abstract:
Utilizing the easily available isatin-based propargyl amines prepared from isatins, terminal alkynes, and anilines, (2-(quinolin-2-yl)phenyl)carbamates were prepared by a one-pot reaction in sequence, combining the gold-catalyzed Friedel-Crafts cyclization, oxidative umpolung aza-Grob fragmentation, and nucleophilic addition. In this process, gold-catalyzed cyclization of isatin-based propargyl amines gave 1'H-spiro[indoline-3,2'-quinolin]-2-ones, which were oxidized in situ by hypervalent iodine via the aza-Grob fragmentation to afford isocyano intermediates 2-(2-isocyanatophenyl)quinolines. Followed by the nucleophilic addition with alcohol solvents, (2-(quinolin-2-yl)phenyl)carbamates were synthesized. This procedure features easy operation, a wide substrate scope, and mild conditions.
Related Concept Videos
Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
Electrophilic Aromatic Substitution: Friedel–Crafts Alkylation of Benzene
Benzene to Phenol via Cumene: Hock Process
Limitations of Friedel–Crafts Reactions


