Kinetic and thermodynamic control in the synthesis of methylglyoxal thioacetals from 2-ethoxypropenal

Under kinetically controlled conditions, the addition of organylthiols to 2-ethoxypropenal follows the Markovnikov rule to give 2-ethoxy-2-organylthiopropanals which spontaneously isomerize to 1-ethoxy-1-organylthiopropanones in storage or in the presence of an acid catalyst.