Theoretical Study on the Selective 1,2-Reduction of alfa;,beta-Unsaturated Ketones by Hydrogen Transfer Reaction on MgO(100)

BELELLI, PATRICIA GABRIELA; FUENTE, SILVIA A.; FERULLO, RICARDO M.

Chemphyschem

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2022

1439-4235

Catalytic reduction of α,β-unsaturated ketones with MgO has been found to improve selectivity to the desired unsaturated alcohol product. Using the density functional theory, we have studied the competitive hydrogenation of C=O and C=C bonds on Mg(100) employing two α,β-unsaturated ketones: mesityl oxide (MO) and 2-cyclohexenone (CH), with isopropanol (IPA) as hydrogen source. For both ketones, MgO promotes the formation of a six-membered cyclic transition state for selective C=O reductions via a Meerwein-Ponndorf-Verley mechanism. Similar concerted mechanism is also possible for the C=C hydrogenation following an Eley-Rideal mechanism, in which IPA interacts directly with the adsorbed ketone. The activation barriers are smaller for C=O reduction because this bond is activated on MgO(100). The selective C=O reduction is more favorable for CH than for MO due to the tendency of CH to be perpendicularly oriented. The desorption energies of the unsaturated alcohol are lower than the subsequent C=C reductions.