Dihydropyridines in MCRs. Tandem processes leading to modular tetrahydroquinoline systems with up to 6 diversity elements

N-Acylazinium Salts: A New Source of Iminium Ions for Ugi-Type Processes

“…Therefore, new synthetic methodologies aimed at the multicomponent assembly of heterocyclic systems is of great importance. In connection with our previous studies on the reactivity of dihydroazines in MCRs, we report here our results on the direct functionalization of azines.…”

“…The method is capable of introducing different carbamoyl groups into heterocyclic systems (in a formal umpolung process) to yield either 1,2-dihydro derivatives or, through an oxidative treatment, the corresponding aromatic compounds. Among the synthetic possibilities of compounds 2 , a particularly attractive one is to be engaged in a subsequent MCR, since this would further enhance the molecular diversity introduced in the process. , This method will contribute to expand the direct functionalization of heterocyclic scaffolds, a pivotal issue in synthetic, combinatorial, and medicinal chemistry . Further reactivity studies and synthetic applications of this methodology are in progress in our laboratory.…”

Multicomponent Reactions with Dihydroazines: Efficient Synthesis of a Diverse Set of Pyrido-Fused Tetrahydroquinolines

“…In this way, successful one-pot processes allowing the incorporation of cyano, phosphonate, and aminouracil residues were developed, and the corresponding products 5a − a ‘, 5b − b ‘, and 5c − c ‘ were prepared as the usual diastereomeric mixtures at the α-ester position, thus controlling the relative configuration of three of the four centers. The stereochemical outcome can be rationalized by considering the preferential attack of the dihydropyridine ring upon the iminium ion taking place from its less substituted face 4 MCRs with In Situ-Formed DHPs …”

Selectivity in multiple multicomponent reactions: types and synthetic applications

“…Similarly, a suitably substituted aldehyde participates in a GBB MCR to yield an adduct which participated in standard Ugi–Passerini processes through the carboxylic acid functional group, untouched in the first MCR (Scheme 10) [39]. Furthermore, Reissert or Reissert/Ugi reactions can be linked with Povarov MCRs through the intermediacy of the enamine-containing adducts from the former processes (Scheme 10) [40].…”