A bis(pyridyl)-N-alkylamine/Cu(i) catalyst system for aerobic alcohol oxidation

Lindie Marais; Jordi Burés; Johan H L Jordaan; Selwyn Mapolie; Andrew J Swarts

doi:10.1039/c7ob01383c

A bis(pyridyl)-N-alkylamine/Cu(i) catalyst system for aerobic alcohol oxidation

Org Biomol Chem. 2017 Aug 23;15(33):6926-6933. doi: 10.1039/c7ob01383c.

Authors

Lindie Marais¹, Jordi Burés, Johan H L Jordaan, Selwyn Mapolie, Andrew J Swarts

Affiliation

¹ Catalysis and Synthesis Research Group, Focus Area for Chemical Resource Beneficiation, North-West University, 11 Hoffman Street, Potchefstroom 2520, South Africa. Andrew.Swarts@nwu.ac.za.

PMID: 28776055
DOI: 10.1039/c7ob01383c

Abstract

Herein a bis(pyridyl)-N-alkylamine/Cu^I/TEMPO/NMI catalyst system is reported for aerobic oxidation of a variety of primary alcohols to the corresponding aldehydes using readily available reagents, at room temperature and ambient air as the oxidant. ESI-MS analysis of the reaction showed the formation of a [(L1)(NMI)Cu^II-OOH]⁺ species, which is a key intermediate in the alcohol oxidation reaction. Evaluation of the effect of reaction parameters on the initial rate of the reaction allowed us to obtain the optimum conditions for catalytic activity. The careful choice of reaction solvent allowed for the oxidation of 4-hydroxybenzyl alcohol, a substrate which proved problematic in previous studies. In the case of 2-pyridinemethanol as substrate, experimental evidence shows that catalytic activity is diminished due to competitive inhibition of the catalyst by the alcohol substrate.