A Convenient Synthesis of 4‐CF3‐Quinolines from 1‐Trifluoromethyl‐prop‐2‐yne 1‐Iminium Salts and Arylamines. Issue 20 (26th May 2021)

• Record Type: Journal Article
• Authors: Schneider, Thomas; Fleischmann, Maximilian; Hergesell, Daniel; Majstorović, Nicola; Maas, Gerhard
• Is Part Of: European journal of organic chemistry. Issue 20(2021)
• Page Start: 2869
• Page End: 2886
• Publication Date: 2021-05-26
• Subjects: Alkynes -- Iminium salts -- Organofluorine heterocycles -- Quinolines -- Synthetic methods; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.202100378
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: A convenient synthesis of 4‐trifluoromethyl‐quinolines from 1‐trifluoromethyl‐prop‐2‐yne 1‐iminium triflates and anilines in a one‐pot two‐step Michael addition/intramolecular cyclization sequence is reported. With ring‐substituted anilines, a wide range of 4‐CF3 ‐quinolines bearing additional substituents and functional groups in the C‐2, C‐6, and C‐8 positions were prepared, mostly in high yields. Even a 4‐CF3 ‐5‐Me‐quinoline could be obtained. From mono‐Boc protected 1, 4‐ and 1, 3‐phenylenediamine, 2‐aryl‐substituted 6‐amino‐4‐CF3 ‐quinoline and 7‐amino‐4‐CF3 ‐quinoline, respectively, were prepared. 4‐CF3 ‐benzo[ h ]quinolines were obtained from the mentioned acetylenic iminium salts and 1‐naphthylamine. With N ‐monosubstituted aromatic amines such as N ‐methylaniline and 1, 2, 3, 4‐tetrahydroquinoline, N ‐substituted 4‐CF3 ‐quinolinium salts and pyrrolo[1, 2‐ a :3, 4‐ c ']diquinoline derivatives bearing two CF3 substituents could be prepared. Abstract : 1‐CF3 ‐substituted acetylenic iminium salts are excellent C3 ‐building blocks for the regioselective and generally high‐yielding synthesis of 4‐trifluoromethyl‐quinolines from a wide range of ring‐substituted anilines and of 4‐CF3 ‐benzo[h]quinolines from 1‐naphthylamine. With N‐monosubstituted anilines, 4‐CF3 ‐quinolinium salts and pyrrolo[1, 2‐a;3.4‐c']diquinolines can be obtained.