Imperial College London
Alternate

Professor Chris Braddock

Faculty of Natural Sciences, Department of Chemistry

Professor of Organic Chemistry
 
 
 
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Contact

 

+44 (0)20 7594 5772c.braddock

 
 
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Location

 

601EMolecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Citation

BibTex format

@article{Lo:2019:10.1002/ejoc.201900109,
author = {Lo, Q and Sale, D and Braddock, D and Davies, R},
doi = {10.1002/ejoc.201900109},
journal = {European Journal of Organic Chemistry},
pages = {1944--1951},
title = {New insights into the reaction capabilities of ionic organic bases in cu-catalysed amination},
url = {http://dx.doi.org/10.1002/ejoc.201900109},
volume = {2019},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The application of ionic organic bases in the coppercatalyzed amination reaction (Ullmann reaction) has been studied at room temperature, with submol% catalyst loadings, and with more challenging amines at elevated temperatures. The cation present in the base has been shown to have little effect on the reaction at standard catalyst and ancillary ligand loadings, whereas the choice of anion is crucial for good reactivity. A substrate scope carried out at room temperature with the best performing bases, TBAM and TBPM, showed both bases to be highly effective under these mild reaction conditions. Moreover, under submol % catalyst loadings and room temperature conditions, TBPM gave good to excellent yields for a number of different amines and functionalized aryl iodides (14 examples). However, reactions involving more challenging amines gave little or no yield. By using more forceful conditions (120 °C) moderate to excellent yields of crosscoupled products containing more challenging amines was achievable using TBPM and to a lesser extent with TBAM. As part of this work a study on the stability of the organic bases at 120 °C was undertaken. TBAM is shown to decompose to give nBu3N and monobutylmalonate at higher temperatures, and this can be correlated to a decrease in performance in the coupling reaction. The phosphonium cations in TBPM did not undergo analogous reactivity but were shown instead to experience some degree of deprotonation at the αCH2 to generate phosphonium ylides. This however did not lead to a significantly degradation in the activity of the TBPM in the crosscoupling reaction.
AU  - Lo,Q
AU  - Sale,D
AU  - Braddock,D
AU  - Davies,R
DO  - 10.1002/ejoc.201900109
EP  - 1951
PY  - 2019///
SN  - 1099-0690
SP  - 1944
TI  - New insights into the reaction capabilities of ionic organic bases in cu-catalysed amination
T2  - European Journal of Organic Chemistry
UR  - http://dx.doi.org/10.1002/ejoc.201900109
UR  - http://hdl.handle.net/10044/1/67287
VL  - 2019
ER  -
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