Synergistic effects between reactions, reagents and catalysts can lead to minor heats of reaction and occur as an inherent result of multi-component reactions (MCRs) and their extensions. They enable syntheses to be performed at a low energy level and the number of synthesis steps to be drastically reduced in comparison with 'classical' two-component reactions. The very high potential for variability, diversity and complexity of MCRs additionally generates an extremely diverse range of products, thus bringing us closer to the aim of being able to produce tailor-made and extremely low-priced materials, drugs and libraries.Keywords: multicomponent reaction; MCR; post condensation modification PCM; post condensation cyclisation PCC; MFCR; multifunction catalysis; variability; diversity; complexity; efficiency of synthesis.
PrologueThe high discrepancy between traditional feasibility mania and rational efficiency assessment in chemical synthesis became immediately apparent to the author while working on his thesis and during everyday laboratory life. On the one hand, classic peptide synthesis with an inefficient, extremely high number of synthesis steps and on the other hand, elegant multicomponent reactions that can make such efforts unnecessary. This double strategy in chemical synthesis has given the author cause to reflect (Picture 2) on how to close this gap using a consistent procedure. Picture 2. Problem in chemical syntheses relating to terms of producibility, ecology and economy.