Chemistry of Organo Halogenic Molecules. Part 229. The Role of Iodine in Acetyl Group Transfer to Oxygen-containing Molecules under Solvent-free Reaction Conditions

Iodine was shown to be an efficient catalyst for the conversion of phenyl-substituted aldehydes to the corresponding 1,1-diacetate derivatives under solvent-free reaction conditions (SFRC), which are superior to the classical solution conditions. It was demonstrated that the order of the addition of reactants was of fundamental importance; the ability of substituents on the phenyl ring modified reactivity irrespectively to electronic properties, the pentafluorophenyl group significantly reduced reactivity of the aldehyde. Alcohols yielded acetates; acetic anhydride was found to be the most efficient reagent; isopropenyl acetate and vinyl acetate were less reactive; however the pentafluorophenyl group enhanced reactivity with the latter two reagents. Beside the esterification of benzyl alcohol and its pentafluorophenyl analogue, the formation of acetals was also observed.