ChemInform Abstract: Recent Progress in the Chemistry of Multicomponent Reactions

The chemistry of multicomponent (MCRs) and isocyanides belongs to three periods: In the century 1859-1958, isocyanide chemistry was moderately active and was separate from the classical of the MCRs. In the next period, isocyanides became well available, and MCRs of isocyanides became the most variable way of forming chemical compounds. The year 1993 began a new era of the formation and investigation of the products and the libraries of the Ugi reaction (U-4CR) and higher MCRs of the iso- cyanides. This chemistry is primarily accomplished in the industrial search and preparation of new pharmaceutical and plant-protecting products. FIRST CENTURY OF THE CHEMISTRY OF ISOCYANIDES AND MCRs Besides the usual multistep syntheses, an increasing number of organic chemical compounds are formed by multicomponent (MCRs) that convert more than two educts directly into their prod- ucts by one-pot reactions. In contrast to the multistep syntheses, the MCRs need minimal work, and they have often quantitative yields. The first MCRs were accomplished in 1838 when Laurent and Gerhardt (1) formed the benzoylazotide from bitter almond oil and ammonia via benzaldehyde, hydrogen cyanid. The chem- istry of the MCRs officially began twelve years later, when Strecker (2) introduced the general forma- tion of α -aminocyanides from ammonia, carbonyl compounds, and hydrogen cyanide. The preparation of heterocyclic compounds by MCRs was introduced in the early 1880s (3). Since then, many name reactions of MCRs were developed. This ended in 1960, when Hellmann and Opitz (4) published the α -Aminoalkylierung book where they demonstrated that all of these classical are α -aminoalkylations of nucleophiles, including the preparations of heterocyclic products by MCRs that are α -aminoalkylations and subsequent ring-forming of further bifunctional educts. In 1859, the chemistry of the isocyanides began when Lieke (5) formed the allyl isocyanide from allyl iodide and silver cyanide. Eight years later, Gautier (6) formed alkylisocyanides thus generally, and at the same time Hofmann (7) introduced the formation of isocyanides from primary amines, chlo- roform, and potassio hydroxyde. For a whole century, only twelve isocyanides had been produced (8). The chemistry of isocyanides is fundamentally different from the rest of organic chemistry, since they are the only chemical compounds with divalent carbon atoms C II , and all of their chemical reac- tions correspond to conversions of the divalent carbon atoms C II into the tetravalent carbon atoms C IV . In 1921, Passerini (8,9) introduced the first MCRs of the isocyanides. They react with carboxylic acids and carbonyl compounds into the acyloxy-carbonamides. This first century of isocyanide chem- istry contained important progress, but overall was a rather empty part of chemistry.