A research group led by Professor Junji Ichikawa from Faculty of Pure and Applied Sciences, the University of Tsukuba, has used a reaction process involving transition metals known as β-fluorine elimination to discover that they are able to consecutively and efficiently cleave the carbon–fluorine bonds of fluoroalkenes and successfully synthesize carbocyclic compounds as an end product. Since carbon–fluorine bonds have high binding energy, it has been considered difficult to cleave these bonds and perform chemical conversion under benign conditions. These bond structures are found in all greenhouse gases known as CFCs, and the development of an organic synthesis reaction that will cleave them has been a topic that is both challenging and of the utmost importance for the modern era. In this study, a nickel complex and alkynes were used to consecutively and selectively cleave the carbon–fluorine bonds in a type of CFC known as trifluoromethyl-1-alkene under benign, room-temperature conditions and easily synthesize cyclopentadiene, a carbocyclic compound that is useful as a synthetic intermediate for products such as pharmaceuticals or synthetic resins. This reaction holds the promise of being a new, all-purpose chemical conversion method for fluorine-containing compounds such as unneeded CFCs—in essence, a more efficient method of recycling those compounds. The results of this research were published on May 18, 2014 in the online bulletin edition of Angewandte Chemie International Edition, a scientific journal from the Federal Republic of Germany, and were considered to be of such value that they made it the front cover.

Professor Junji Ichikawa

Original Paper

Tomohiro Ichitsuka, Takeshi Fujita, Tomohiro Arita, Junji Ichikawa, Double CF Bond Activation through b-Fluorine Elimination: Nickel-Mediated [3+2] Cycloaddition of 2-Trifluoromethyl-1-alkenes with Alkynes**, Angewandte Chemie International Edition 53(29). doi: 10.1002/anie.201402695 (18May2014)