Three-component synthesis of polysubstituted pyrroles from α-diazoketones, nitroalkenes, and amines

Rhodium(III)-catalyzed alkenyl C-H bond functionalization: convergent synthesis of furans and pyrroles

Ring in the new: a new annulation for the efficient synthesis of substituted furans and pyrroles is reported. The Rh(III) -catalyzed reaction of O-methyl α,β-unsaturated oximes with aldehydes and N-tosyl imines affords secondary alcohol and amine intermediates, respectively. Cyclization and aromatization occurs under the reaction conditions to provide access to biologically relevant furans and pyrroles in good yields. Cp*=C(5)Me(5), DCE=1,2-dichloroethane, THF=tetrahydrofuran.

InCl3 Catalysed One-Pot Synthesis of Substituted Pyrroles and 2-Pyrones

An efficient InCl3 catalysed one-pot strategy has been developed for the synthesis of tetra-substituted pyrroles and tri-substituted 2-pyrones in very good yields. Tetra-substituted pyrroles were prepared from 1,4-enediones and β-dicarbonyls employing NH4OAc as a nitrogen source, through a combination of Michael addition and Paal–Knorr methods. Tri-substituted 2-pyrones were synthesised from 1,4-ynediones and appropriate β-dicarbonyls using a sequential Michael addition and 6-exo-trig cyclisation.

A one-pot multicomponent strategy for stereospecific construction of tricyclic pyrrolo[1,2-a]quinolines

A novel multicomponent strategy for the efficient synthesis of tricyclic pyrrolo[1,2-a]quinolines has been described. The bond-forming efficiency, accessibility and generality of this synthesis make it highly attractive to assemble tri-heterocyclic scaffolds.

Modulating the reactivity of functionalized N,S-ketene acetal in MCR: selective synthesis of tetrahydropyridines and thiochromeno[2,3-b]pyridines via DABCO-catalyzed tandem annulation

An efficient and straightforward three-component synthetic protocol was developed to synthesize 1,2,3,4-tetrahydropyridine derivatives or thiochromeno[2,3-b]pyridine derivatives from β-aroylthioacetanilides or β-(2-haloaroyl)thioacetanilides, aldehydes, and aroyl acetonitriles via DABCO-catalyzed tandem [3 + 2 + 1] annulation and S(N)Ar reaction. This synthetic approach has the prominent features of high chemo-, stereo- (or enantio-), and unusual regioselectivity. In the domino processes, at least seven reactive sites were involved, and up to three covalent bonds and one functionalized pyridine ring were generated. This facile and efficient reaction is a quite general for the preparation of tetrahydropyridine derivatives or thiochromeno[2,3-b]pyridine derivatives.

Diversity oriented syntheses of conventional heterocycles by smart multi component reactions (MCRs) of the last decade

A collection of smart multicomponent reactions (MCRs) with continuative post condensation cyclizations (PCCs) is presented to construct conventional three- to seven-membered heterocyclic compounds in diversity oriented syntheses (DOS). These will provide a high degree of applying economical and ecological advantages as well as of practicability. Water, ionic liquids, and solvent-less syntheses as well as use of various forms of energy as microwave and ultrasonic irradiation are examined and discussed.

Multifunctionalized 3-hydroxypyrroles in a three-step, one-pot cascade process from methyl 3-TBSO-2-diazo-3-butenoate and nitrones

The synthesis of N-aryl-2-carboxyl-3-hydroxy-5-arylpyrroles has been achieved in high yield by the combination of a TBSO-substituted vinyldiazoacetate and nitrones in a one-pot cascade process involving copper-catalyzed Mannich addition, dirhodium-catalyzed dinitrogen extrusion and N-OTBS insertion, and acid-promoted aromatization (elimination).