Promoting effect of alcohols and formic acid on Au-catalyzed one-pot myrtenol amination

The one-pot myrtenol amination with aniline was performed over Au (3 wt.%)/ZrO2 catalyst using methanol, 2-propanol or formic acid as hydrogen donors with the aim to enhance the target amine yield. It was found that addition of small amounts of 2-propanol or formic acid (additive/myrtenol ratio equals to 0.5 and 0.25, respectively) led to the increase of the target amine yield up to 68 and 65%, respectively, compared with 52% amine yield in the absence of additives. However, further increase of additive amount decreased amine formation: 2-propanol interacted with aniline competing with myrtenol; formic acid introduction into the reaction mixture suppressed activity of Au/ZrO2 catalyst due to strong adsorption of formic acid and decomposition products on the support basic sites strongly required for the initial alcohol activation. Methanol was found not to be effective as a hydrogen donor for one-pot alcohol amination.