Das, Tamal Kanti ; Ghosh, Avik ; Balanna, Kuruva ; Behera, Pradipta ; Gonnade, Rajesh G. ; Marelli, Udaya Kiran ; Das, Abhijit Kumar ; Biju, Akkattu T. (2019) N-Heterocyclic Carbene-Catalyzed Umpolung of Imines for the Enantioselective Synthesis of Dihydroquinoxalines ACS Catalysis, 9 (5). pp. 4065-4071. ISSN 2155-5435
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Official URL: http://doi.org/10.1021/acscatal.9b00737
Related URL: http://dx.doi.org/10.1021/acscatal.9b00737
Abstract
N-heterocyclic carbene (NHC) organocatalysis is widely employed for the umpolung of aldehydes, and recently to the umpolung of Michael acceptors and aldimines. Described herein is the NHC-organocatalyzed umpolung of aldimines for the enantioselective synthesis of nitrogen heterocycles. The bisimines generated from the condensation of 1,2-phenylene diamines and salicylaldehydes undergo intramolecular cyclization in the presence of a chiral NHC catalyst resulting in the for-mation of dihydroquinoxalines in moderate to good yields and er values. Detailed DFT studies shed light on the role of –OH groups in stabilizing the initially generated aza-Breslow intermediates via intramolecular hydrogen bonds. Preliminary pho-tophysical studies on the synthesized dihydroquinoxalines revealed that these molecules can be used for the sensing of vari-ous acids and bases.
Item Type: | Article |
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Source: | Copyright of this article belongs to American Chemical Society |
ID Code: | 128607 |
Deposited On: | 03 Nov 2022 06:44 |
Last Modified: | 03 Nov 2022 06:44 |
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