Electrochemical Methodologies for the Carboxylation Reactions in Organic Synthesis. An Alternative Re-use of Carbon Dioxide

Today, the need to control carbon dioxide production and emission has become an important target for both scientific and industrial world. To this purpose, the use of carbon dioxide as raw material and building block for the synthesis of complex molecules represents an efficient tool to its recycle and re-use. A great effort has been made in order to reconvert carbon dioxide to valuable organic compounds and utilize it as a source of carbon in organic synthesis. However, carbon dioxide is considered as an inert molecule and the electrochemical methodologies represent a valuable tool for its "activation" either in a direct or indirect way. In this review, the main electrochemical methodologies using carbon dioxide for the carboxylation of a large number of organic compounds appeared in the literature in the last decade, will be reported. In particular, the incorporation reaction of carbon dioxide molecule in alkenes, carbonyl compounds, alcohols, epoxides, amines and halides yielding carboxylic acids, linear and cyclic carbamates and carbonates will be discussed. The electrochemical methods that utilize CO2 in carboxylation reactions will be considered in detail, to provide a detailed picture of the state of the art. Keywords: Green chemistry, carbon dioxide, electroorganic synthesis, electrochemical carboxylation, carboxylic acids, carbonates, carbamates.