Abstract The selective preparation of monoketals 3a-f from pentaerythritol 1 and cyclic, acyclic, aromatic, and aliphatic ketones 2a-f was achieved by a facile method. The extreme polarity and low solubility of pentaerythritol in almost all organic solvents were the main difficulties to be overcome for the preparation of monoketals in good yields and high selectivity. A benzene-dimethylformamide (40: 60) mixture proved to be excellent for the ...