ABSTRACT
In multicomponent reactions (MCRs) more than two reactants form a single product. The integrative nature of MCRs is increasingly attractive when a rapid increase in molecular diversity is desired. MCRs have been used in total synthesis, drug discovery, and bioconjugation. Novel scaffolds are becoming more sought after as pathogens mutate to become resistant to current medications, and as other diseases, such as Alzheimer's, cancer, and others, begin to be better understood by scientists. While MCRs may not be directly responsible for the drugs that treat these diseases in the future, they will certainly be involved as scientists search for tomorrow's remedies. Isocyanide-based reactions form the backbone of MCR chemistry; the most common examples are the Passerini reaction and the Ugi reaction. The Passerini reaction involves a carboxylic acid, aldehyde or ketone, and isocyanide, and yields α-acyloxy amides. The electrophilic activation of the carbonyl group is followed by a nucleophilic attack by the isocyanide.
