Transformation of ethers into aldehydes or ketones: a catalytic aerobic deprotection/oxidation pathway

A facile and efficient protocol for direct transformation of p-methoxybenzyl (PMB) ethers to aldehydes or ketones via a catalytic aerobic oxidation process has been developed. The reaction was performed with the combination of catalytic amounts of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,2,6,6-tetramethylpiperidine N-oxy (TEMPO), and tert-butyl nitrite (TBN), with molecular oxygen as terminal oxidant. A variety of PMB ether substrates derived from benzylic alcohols, heteroaromatic alcohols, and aliphatic alcohols, were converted to their corresponding carbonyl compounds in good conversions and selectivities. (C) 2015 Elsevier Ltd. All rights reserved.