Synthesis 2018; 50(14): 2655-2677
DOI: 10.1055/s-0037-1609733
review
© Georg Thieme Verlag Stuttgart · New York

Recent Advances in the Regioselective Synthesis of Indoles via C–H Activation/Functionalization

Inder Kumar ‡
a   Natural Product Chemistry and Process Development Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India
b   Academy of Scientific and Innovative Research, CSIR-IHBT, Palampur, Himachal Pradesh 176061, India   Email: upendra@ihbt.res.in   Email: upendraihbt@gmail.com
,
Rakesh Kumar ‡
a   Natural Product Chemistry and Process Development Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India
b   Academy of Scientific and Innovative Research, CSIR-IHBT, Palampur, Himachal Pradesh 176061, India   Email: upendra@ihbt.res.in   Email: upendraihbt@gmail.com
,
Upendra Sharma*
a   Natural Product Chemistry and Process Development Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India
b   Academy of Scientific and Innovative Research, CSIR-IHBT, Palampur, Himachal Pradesh 176061, India   Email: upendra@ihbt.res.in   Email: upendraihbt@gmail.com
› Author Affiliations
This work is supported by the Science and Engineering Research Board, India (EMR/2014/001023). R.K. and I.K. acknowledge UGC, New Delhi for Junior Research Fellowships.
Further Information

Publication History

Received: 25 January 2018

Accepted after revision: 05 March 2018

Publication Date:
28 May 2018 (online)


These authors contributed equally to this review.

Abstract

Indole is an important heterocyclic motif that occurs ubiquitously in bioactive natural products and pharmaceuticals. Immense efforts have been devoted to the synthesis of indoles starting from the Fisher indole synthesis to the recently developed C–H activation/functionalization-based methods. Herein, we have reviewed the progress made on the regioselective synthesis of functionalized indoles, including 2-substituted, 3-substituted and 2,3-disusbstituted indoles, since the year 2010.

1 Introduction

2 Metal-Catalyzed Synthesis of 2-Substituted Indoles

3 Metal-Catalyzed Synthesis of 3-Substituted Indoles

4 Metal-Free Synthesis of 3-Substituted Indoles

5 Metal-Catalyzed 2,3-Disubstituted Indole Synthesis

5.1 Metal-Catalyzed Intramolecular 2,3-Disubstituted Indole Synthesis

5.2 Metal-Catalyzed Intermolecular 2,3-Disubstituted Indole Synthesis

6 Metal-Free 2,3-Disubstituted Indole Synthesis

6.1 N-Protected 2,3-Disubstituted Indole Synthesis

6.2 N-Unprotected 2,3-Disubstituted Indole Synthesis

7 Applications

8 Summary and Outlook