Issue 7, 2016

A mechanistic study on guanidine-catalyzed chemical fixation of CO2 with 2-aminobenzonitrile to quinazoline-2,4(1H,3H)-dione

Abstract

The organic base-catalyzed mechanism of chemical fixation of CO2 with 2-aminobenzonitrile to quinazoline-2,4-(1H,3H)-dione has been studied by means of density functional theory (DFT) calculations on such reactions in the presence of two typical organic guanidines: 1,1,3,3-tetramethylguanidine (TMG) and 1,5,7-triazabicyclo[4.4.0]dec-1-ene (TBD). The calculations reveal that the guanidine-catalyzed reaction prefers to proceed through a general base mechanism rather than the CO2 activation mechanism that involves the formation of guanidine–CO2 adducts. In the general base mechanism, the guanidine primarily plays a catalytic role as a strong base to promote the fixation of CO2 by the amino group of 2-aminobenzonitrile, leading to a carbamate intermediate. Meanwhile, the acidity of guanidinium and the synergistic catalysis from the amino group of 2-aminobenzonitrile are also found to be crucial for lowering energy barriers of intramolecular nucleophilic attack from the carbamate to the nitrile group and the isocyanate intermediate formation via the ring-opening step. In comparison with the TBD-catalyzed reaction, the catalytic advantage of TMG is exerted at the less H-bonding interaction between [TMGH]+ guanidinium and the carbamate anion, owing to its own acyclic framework.

Graphical abstract: A mechanistic study on guanidine-catalyzed chemical fixation of CO2 with 2-aminobenzonitrile to quinazoline-2,4(1H,3H)-dione

Supplementary files

Article information

Article type
Research Article
Submitted
01 Mar 2016
Accepted
27 Apr 2016
First published
28 Apr 2016

Org. Chem. Front., 2016,3, 823-835

A mechanistic study on guanidine-catalyzed chemical fixation of CO2 with 2-aminobenzonitrile to quinazoline-2,4(1H,3H)-dione

W. Li, N. Yang and Y. Lyu, Org. Chem. Front., 2016, 3, 823 DOI: 10.1039/C6QO00085A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements