Waste-Mediated Reactions

The development of sustainable tandem reactions by "waste as catalyst/promoter" approach offers a new opportunity to develop new chemistry aiming at maximizing the atom utilization of a process. Considering the resource-intensive nature of the synthetic industry and its bottleneck problems such as energy shortage and environmental pollution of modern society, this strategy will find more applications in synthetic chemistry, especially in the case of multistep synthesises involving reactions that inevitably generate by-products (e.g., Wittig, Grignard, and substitution reaction). This chapter introduces reactions that internally utilize the waste by two categories: waste-promoted single reactions and waste-promoted tandem reactions. As perceptible examples of waste-promoted tandem reactions are very limited, the racemic or achiral versions of such sustainable tandem reactions are included as well.