eCite Digital Repository
Disclosure of some obscure mechanistic aspects of the copper-catalyzed click reactions involving N2 elimination promoted by the use of electron-deficient azides from a DFT perspective
Citation
Roohzadeh, R and Nasiri, B and Chipman, A and Yates, BF and Ariafard, A, Disclosure of some obscure mechanistic aspects of the copper-catalyzed click reactions involving N2 elimination promoted by the use of electron-deficient azides from a DFT perspective, Organometallics, 38, (2) pp. 256-267. ISSN 0276-7333 (2019) [Refereed Article]
Copyright Statement
© 2018 American Chemical Society
DOI: doi:10.1021/acs.organomet.8b00691
Abstract
We have used density functional theory to explore the copper(I)-catalyzed reaction between a mesyl azide and a terminal alkyne that leads to a ketenimine whose interaction with nucleophilic water produces an amide. It is well reported in the literature that a cuprated triazole intermediate is formed during the course of such a catalytic cycle. In this contribution, we investigated the stability of this key intermediate by varying the R substituent on the azide and found that electron-withdrawing R substituents make this intermediate more reactive toward ring opening/N2 elimination; an electron-withdrawing R substituent facilitates this process by weakening the N–N bond being cleaved. We also rationalized why the cycloaddition step in this class of click reactions is required to proceed via a binuclear mechanism. The copper(I) acetylide intermediate formed during the catalysis gains extra stability upon scavenging a second Cu complex, resulting in the cycloaddition step occurring with a lower activation barrier. We also noticed that, similar to the ring closure step, inclusion of a second Cu complex may accelerate the ring opening/N2 elimination process. It was shown that the ketenimine needs to coordinate to a copper center via its nitrogen atom in order to be activated toward hydrolysis.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | density functional theory, activation energy, click reactions, electron-deficient azides |
Research Division: | Chemical Sciences |
Research Group: | Organic chemistry |
Research Field: | Physical organic chemistry |
Objective Division: | Expanding Knowledge |
Objective Group: | Expanding knowledge |
Objective Field: | Expanding knowledge in the chemical sciences |
UTAS Author: | Chipman, A (Mr Antony Chipman) |
UTAS Author: | Yates, BF (Professor Brian Yates) |
UTAS Author: | Ariafard, A (Associate Professor Alireza Ariafard) |
ID Code: | 134447 |
Year Published: | 2019 |
Funding Support: | Australian Research Council (DP180100904) |
Web of Science® Times Cited: | 8 |
Deposited By: | Chemistry |
Deposited On: | 2019-08-13 |
Last Modified: | 2019-12-09 |
Downloads: | 0 |
Repository Staff Only: item control page