En Route to Intermolecular Cross-Dehydrogenative Coupling Reactions

Cross-coupling reaction between two C–H bonds has become a fundamental strategy in synthetic organic chemistry. With its increasing importance in green chemistry, atom economy, and step economy, its development has sky-rocketed within the last 20 years, with the term “cross-dehydrogenative coupling (CDC)” popularized and progressed by the group of Li and others to describe direct Y–Z bond formations from Y–H and Z–H bonds under oxidative conditions. Among all types of CDC reactions, the C–C bond formations are of prime importance in building up the molecular complexity but their categorization currently remains disarray due to a wide diversity, resulting in frequent display in separate topics. In this Perspective, a contemporary categorization via C–H activation strategies is presented herein, which could be vital for future CDC designs. With this mechanism-based categorization and discussion, we wish that this minireview will help more synthetic chemists gain insight into the design of CDC reactions and inspires more ideas on this topic.