Hydrogen transfer methylation of ketones using methanol as the electrophile
N-heterocyclic carbenes, when compared to their phosphine analogues, offer stronger metal–ligand bond formation and better stability properties. The N-heterocyclic carbene iridium complex was found to be the first catalyst to be used at room temperature with low catalyst loading. In these transition-metal catalyzed hydrogen transfer reactions the mechanism is as follows: the catalyst removes the hydrogen atoms from an alcohol to generate an aldehyde, which undergoes bond formation with another nucleophile in a condensation reaction, after which the metal hydride formed from the oxidation of the alcohol reduces this newly generated intermediate to give the final product. The simplest alcohol: methanol is an important compound in the chemical industry, and its transition-metal catalyzed dehydrogenation has been described previously and report on the potential application of methanol in C-C bond formation via hydrogen transfer reactions. The aim of this study is to perform a quantum-chemical investigation in order to reveal the reaction mechanism and hence to understand the selectivity process of the catalyst in this reaction.