Automated search for chemical reaction pathways by the artificial force induced reaction method: Toward practical applications in synthetic organic chemistry

Theory has become one of important tools in synthetic organic chemistry. The transition state (TS) of chemical reactions can be visualized by geometry optimizations. This helps to design novel reactions. However, there has been a serious problem. That is, how to prepare initial structures for all relevant TSs. An optimization starting from a bad structure fails to converge. Moreover, geometry optimization cannot find unexpected TSs. The latter prohibits reliable analysis and prediction of mechanisms in highly complicated, multistep reactions. In order to solve this problem, we have developed automated reaction path search methods. In this paper, the artificial force induced reaction (AFIR) method and some examples of its applications are described. The AFIR method would expand applicability of theory dramatically.