Reductive aromatization of oxindoles to 3-substituted indoles. Issue 28 (9th July 2020)

• Record Type: Journal Article
• Authors: Mandal, Tirtha; Chakraborti, Gargi; Dash, Jyotirmayee
• Is Part Of: Tetrahedron letters. Volume 61:Issue 28(2020)
• Publication Date: 2020-07-09
• Subjects: Bis-indoles -- Hydride transfer -- Indolinium ion -- 3-Indole -- Oxindole -- Reductive aromatization; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2020.152109
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Practical and scalable synthetic route to 3-indoles. Partial reduction-aromatization of oxindoles to 3-indoles using LiAlH4 . The reaction proceeds via an indolinium ion intermediate. Synthesis of a diverse class of 3-indoles and bis-indoles. A quick access to tryptamine. Abstract: A practical and scalable approach for the synthesis of 3-substituted indoles is delineated via hydride nucleophilic addition to 3-substituted-2-oxindoles. The reaction proceeds through reductive aromatization involving indolinium ion intermediate. A wide range of 3-functionalized indoles have been synthesized. The method is employed for the synthesis of 3, 3ʹ-bis-indoles and a dimeric 3-indole derivative. Moreover, this protocol is used to obtain naturally occuring amino acid tryptamine.