Development of Photo-Driven Dehydrogenative Coupling with H2 Evolution

The 12 Principles of Green Chemistry, established by Paul Anastas and John Warner in 1998, advocate for the design of inherently clean systems, prioritizing the prevention of waste, atom economy, and the minimization of derivatives, rather than focusing on remediation. Implementing such a framework necessitates the invention of innovative chemical transformations that fundamentally avoid byproduct formation. Dehydrogenative coupling, characterized by the evolution of dihydrogen (H2) as the co-product, exemplifies these green chemistry ideals and stands as a compelling objective for the synthetic community. Following our 2020 discovery of the dehydrogenative coupling between aldehydes and alkylbenzenes to produce benzyl ketones, we have endeavored to broaden the reaction scope and uncover the fundamental mechanisms governing the unique selectivity. This article details our comprehensive investigations into these dehydrogenative coupling processes.