N-Heterocyclic-Carbene-Catalyzed Umpolung of Imines

Atanu Patra; Subrata Mukherjee; Tamal Kanti Das; Shailja Jain; Rajesh G Gonnade; Akkattu T Biju

doi:10.1002/anie.201611268

N-Heterocyclic-Carbene-Catalyzed Umpolung of Imines

Angew Chem Int Ed Engl. 2017 Mar 1;56(10):2730-2734. doi: 10.1002/anie.201611268. Epub 2017 Jan 27.

Authors

Atanu Patra^{1

2}, Subrata Mukherjee^{1

2}, Tamal Kanti Das^{1

2}, Shailja Jain³, Rajesh G Gonnade⁴, Akkattu T Biju^{1

2}

Affiliations

¹ Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune-, 411008, India.
² Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110020, India.
³ Physical/Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune-, 411008, India.
⁴ Centre for Materials Characterization, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune-, 411008, India.

PMID: 28128506
DOI: 10.1002/anie.201611268

Abstract

N-Heterocyclic carbene (NHC) catalysis has been widely used for the umpolung of aldehydes, and recently for the umpolung of Michael acceptors. Described herein is the umpolung of aldimines catalyzed by NHCs, and the reaction likely proceeds via aza-Breslow intermediates. The NHC-catalyzed intramolecular cyclization of aldimines bearing a Michael acceptor resulted in the formation of biologically important 2-(hetero)aryl indole 3-acetic-acid derivatives in moderate to good yields. The carbene generated from the bicyclic triazolium salt was found to be efficient for this transformation.

Keywords: N-heterocyclic carbenes; imines; indoles; organocatalysis; umpolung.

Publication types

Research Support, Non-U.S. Gov't