Green chemistry: The development of cross-dehydrogenative coupling (CDC) for chemical synthesis

Social, economic, and environmental concerns about chemical production have been increasing. These concerns all originate from the inefficiency of conventional chemical syntheses. On the basis of the "E-factor", a concept of the "extended E-factor" is proposed in the article and is used to correlate various industrial sectors and the average number of synthetic steps involved in those sectors. Based on this analysis, the most fundamental way to eliminate waste formation is to develop new chemical reactivity that can greatly shorten the steps involved in a chemical synthesis. In classical organic transformations, a "functional group" is required. In efforts to develop new chemical reactivities that do not need extra steps for generating functional groups, we have recently developed various cross-dehydrogenative coupling (CDC) methodologies to construct functional molecules by directly using C-H bonds. This article describes the progress of our group's research endeavor.