Friedel‐Crafts‐Type Reaction of (Het)Arenes with Aldehydes/Ketones under Acid‐Free Conditions using Neutral Ionic Liquid: A Convenient Routes to bis(Indolyl)methanes and Beyond. Issue 3 (9th February 2022)

• Record Type: Journal Article
• Authors: Kumar, Santosh; Rastogi, Sumit K.; Singh, Akansha; Bharati Ahirwar, Mini; Deshmukh, Milind M.; Sinha, Arun K.; Kumar, Ravindra
• Is Part Of: Asian journal of organic chemistry. Volume 11:Issue 3(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-09
• Subjects: Friedel-Crafts -- Carbonyls -- Neutral Ionic Liquid -- Bis(3-indolyl)methane -- Sustainable process; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; 547.005
• DOI: 10.1002/ajoc.202100749
• Languages: English
• ISSNs: 2193-5807

Abstract

Abstract: Acid‐free approach has been demonstrated for Friedel‐Crafts‐type reaction of (het)arenes with carbonyls using neutral ionic liquid (NIL). Methodology is enabled to afford a densely functionalized bis(indolyl)methanes in good to excellent yields. This conditions is also compatible to the synthesis of 3, 3‐di(indol‐3‐yl)indolin‐2‐ones, bis(4‐hydroxycoumarines) and triarylmethanes (total 40 examples; up to 98% yields). Gram‐scale reactions and recycling study were carried out to demonstrate the practicality of present methodology. DFT studies illustrate the catalytic cycle involving simultaneous activation of C=O and indole C−H bond by NIL followed by C−C bond formation. Abstract : A green and sustainable approach have been devised for Friedel‐Crafts‐type reaction of carbonyls under non‐acidic conditions using neutral ionic liquid for the first time. This approach enabled for the synthesis of bis(indolyl)methanes, bis‐ and tris‐arylmethanes in good to excellent yields.