Microwave-assisted, facile, rapid and solvent-free one pot two-component synthesis of some special acylals

A facile, rapid and solvent-free method for the conversion of acids and dihalomethane to the corresponding methylene diesters (acylals) using microwave as activators or assistor, is reported. This method is particularly powerful for the diesterification of carboxylic acids, which afford methylene diesters in good to excellent yields (up to >99%). When the intermediate is trapped, a “double successive SN2 reactions” mechanism is proved.

CH2Cl2 is not an excellent solvent under mild reaction conditions. It is very important for the process development of active pharmaceutical ingredients. In this work, a “double successive SN2 reactions” mechanism is also proved.Figure optionsDownload as PowerPoint slide