CO_2参与构筑C–N,C–C键合成化学品

CO_2-involved synthesis of chemicals by the construction of C–N and C–C bonds

CO2作为一种储量丰富、廉价易得、环境友好的可再生C1资源,将其转化为高附加值的化学品和能源产品已成为一个具有吸引力的研究领域.本文综述了近年来以CO2为C1组分参与构筑C–N,C–C键,合成高附加值化学品方面的研究进展,重点介绍了CO2参与合成噁唑啉酮、喹唑啉二酮、脲、异氰酸酯、咪唑啉酮、苯并咪唑、芳香酸和芳香醛等化合物的相关反应以及催化反应机理研究,并对该领域的研究前景进行了展望.

The emission of CO2 continues to cause serious environmental problems, and there has therefore been a considerable increase in the number of researcher working towards the development of new technologies for the capture and utilization of CO2. As a green, abundant, cheap and renewable C1 resource, CO2 could participate in a wide range of chemical reactions, and could therefore be converted into various value-added chemicals. The conversion of CO2 into other value-added chemicals therefore represents an important way to use CO2, although it contributes very little to reducing the concentration of CO2 in the Earth＇s atmosphere. The green features of CO2-involved chemical processes are of critical importance from the perspective of sustainable development. However, only a few industrial processes have been reported that use CO2 as a raw material because CO2 is thermodynamically stable and chemically inert. To achieve chemical transformations with CO2, a high energy input is generally required, which can be achieved using highly reactive chemicals, specific catalytic systems and high temperature/pressure conditions. Based on these rules, research towards the development of CO2 chemical conversion processes has made great progress. CO2 has been successfully used as a green C1 building block for the production of a variety of different value-added chemicals via the construction of C–H, C–C, C–O and C–N bonds. In particular, CO2 hydrogenation processes and reactions involving the formation of C–O bonds have been widely investigated. Furthermore, the CO2-based synthesis of chemicals via the construction of C–N and C–C bonds has recently attracted considerable attention from numerous researchers, and many excellent results have been reported in literature. For example, aziridines, amino alcohols, acetylenic amines, primary amines, secondary amines, 2-aminobenzonitrile, 1,2-diamines and o-phenylenediamines have all been reacted with CO2 as nitrogen-containing nucleophiles to give the corresponding oxazolidinones, ureas, quinazolines, imidazolidones and benzimidazoles via the formation of C–N bonds. Organozinc compounds, organoboronic esters, dienes, alkenes, alkynes, aryl halides and arenes bearing acidic C–H bonds have also been reacted as nucleophiles with CO2 to give the corresponding aromatic acids and aromatic aldehydes via the construction of C–C bonds. In most cases, it has been demonstrated that catalysts can play a crucial role in the transformation of CO2. It is noteworthy that the chemical transformation of CO2 can be achieved under mild conditions, even at room temperature under atmospheric pressure, through the design of highly efficient catalytic systems. This review will provide a summary of recent advances in the field of CO2-based C–N and C–C bond formation processes for the production of oxazolidinones, quinazolinediones, ureas, isocyanates, imidazolinones, benzimidazoles, aromatic acids and aromatic aldehydes, with particular emphasis on the catalytic systems used to achieve these transformation and possible catalytic reaction mechanisms. This review should therefore provide basic ideas with regard to the use CO2 as an ideal and attractive C1 source in organic synthesis to generate value-added chemicals.