Lithium perchlorate-, acetic anhydride-, and triphenylphosphine-assisted multicomponent syntheses of 4-unsubstituted 2,5-dioxooctahydroquinoline-3-carboxylates and 3-carbonitriles

Abstract

Lithium perchlorate and acetic anhydride were the key additives for the multi-component reaction between 3-aminocyclohex-2-enones, formaldehyde, and malonates yielding adducts that were annulated under acidic conditions to afford bicyclic 2,5-dioxooctahydroquinoline-3-carboxylates. When methyl cyanoacetate was subjected to the same reaction conditions in the presence of a catalytic amount of triphenylphosphine, the bicyclic 2,5-dioxooctahydroquinoline-3-carbonitriles were obtained in a one-flask reaction.

Acetal Addition to Electron-Deficient Alkenes with Hydrogen Atom Transfer as a Radical Chain Propagation Step

“…Crude materials were purified using flash column chromatography (SiO 2 , EtOAc in hexanes) to yield the desired product. Spectroscopic data of known compounds matched those reported in the literature. − …”

Recent developments in multicomponent synthesis of structurally diversified tetrahydropyridines

“…The described MCR was managed to carry out between 3-aminocyclohex-2-enones 128, formaldehyde 15 and methylmalonates 129 to yield an adduct that was annulated under acidic condition using lithium perchlororate and triphenylphosphine as the key additives in catalytic amount to afforded compound 130 (Scheme 27). 51 Apart from these kinds of enamine compounds, ve or six membered cyclic rings bearing double bond substituted with amino group were also acted as enamines related components such as 3-aminocoumarin, aminopyrazoles, anilines etc. Das aldehydes 132 and substituted 3-aminocoumarins 133 and ethers in the presence of 10 mol% hydrated ferric sulphate [Fe 2 (SO 4 ) 3 $yH 2 O] in reuxing acetonitrile, with good yields, high diastereoselectivities and application to a wide range of substrates, using an inexpensive, readily available and recyclable catalyst (Scheme 28).…”

2,3-Dihydropyridin-4(1H)-ones and 3-Aminocyclohex-2-enones: Synthesis, Functionalization, and Applications to Alkaloid Synthesis

“…To this end, we turned our attention to the Knoevenagel reaction (Scheme 42). 38 We devised a novel variant of this reaction using paraformaldehyde (Scheme 43). Because of the reactivity of formaldehyde, the dimerization product 4.156, derived from condensation of the enaminone and formaldehyde, was obtained as the major product.…”