Synthesis of Cyclic Carbonates from Alkenyl and Alkynyl Substrates

As an extensively used chemical product, cyclic carbonate was generally synthesized by transesterification, or the cycloaddition of epoxides, diols with CO2. To reduce the production costs and expand the raw materials, alkenyl and alkynyl substrates have caused much attention in the synthesis of cyclic carbonates, such as olefins, allyl alcohols and propargylic alcohols. Based on the alkenyl substrate, the synthetic process involves a continuous reaction of oxidative carboxylation, with epoxide or halohydrin as an intermediate usually. Therefore, peroxides and nucleophiles (halogens or organic bases) are often necessary in the conversion. Using propargylic alcohols to produce alpha-alkylidene cyclic carbonates, noble metal catalysts play crucial roles in alkynyl activation, and organic bases are considered to assist the intramolecular and intermolecular proton transfer and combine CO2 molecular. As the carboxyl sources in products, inorganic carbonates and organic carboxylic acids also have some applications instead of CO2. In this review, we summarized the synthetic routes of cyclic carbonates from alkenyl and alkynyl substrates in the aspect of catalyst, mechanism and the development tendency.