Multiple Bond‐Forming Transformations: The Key Concept toward Eco‐Compatible Synthetic Organic Chemistry

Recent contributions to the Diversity-Oriented Synthesis (DOS) mediated by iminium ions through multicomponent Mannich-type reactions

“…As opposed to the classical way to synthesize complex molecules by sequential synthesis, MCRs allow the assembly of complex molecules in a one-pot manner. Unlike the usual stepwise formation of individual bonds in the target molecule, the defining attribute of MCRs is the inherent formation of several bonds in one operation without isolating the intermediates (referred to as the bond-forming efficiency, BFE), [9][10][11] changing the reaction conditions, or adding further reagents.…”

“…This finding is in agreement with the atomic economy and bond-forming efficiency (BFE) concepts, which characterizes the multicomponent reactions. [9][10][11] Moreover, in the overall process only a molecule of water is removed as by-product, providing also an environmentally friendly character to our four-component procedure. Hemiacetals are commonly formed when an equivalent of alcohol adds to the carbonyl carbon of an aldehyde.…”

Solvent-free one-pot efficient and highly regioselective access to functionalized thiazolopyridones from α-enolic dithioesters

“…Cascade processes that incorporate multiple bond-forming events in one-pot have come into play, and are of paramount interest in organic synthesis. [1][2][3][4] The synthesis of heterocycles has always been a key aspect, and increasingly attracted the synthetic pursuit of chemists. They are vital part of new drug discovery and indispensable materials in the implementation of any industrial evolution.…”

A novel consecutive three-component Heck-isomerization-Wittig sequence by way of in situ generated aldehydes

“…4 In particular, transition metal-catalyzed carbon-carbon bond forming processes have considerably enhanced the versatility of MCRs in construction of complex structural scaffolds and diversity oriented syntheses. 7 Besides the huge class of Pd-catalyzed cross-coupling reactions, the mechanistically related Heck reaction 8,9 is well received for tolerating many functional groups, most interestingly also aldehydes.…”

“…1,2 Besides addressing the fundamental principles of chemo-, regio-and stereoselectivity, MCRs are inherently efficient to a high degree. With respect to economical and ecological considerations conceptually novel synthetic approaches 3,4 are directed towards the improvement of processes, 5,6 simultaneously reducing the input of work and the output of waste.…”