An Organocatalytic Novel Synthesis of Polyfunctionalized Bis-2,5-dihydrofuran-3-carboxylates via Domino-MCR Strategy

Abstract

For the first time, an elegant, metal‐free and concise route using a pseudo five‐component reaction of dimethyl acetylenedicarboxylate, mono/bis‐ aromatic aldehydes and amines with trifluoroacetic acid as an effective organocatalyst to afford novel and diverse substituted bis‐2,5‐dihydrofuran‐3‐carboxylates in good yields at ambient temperature has been described. The prominent features of this protocol are the energy sustainability, wide range of functional group tolerance, shorter reaction time, no column chromatographic purification, facile experimental and work‐up procedure. The present one‐step, cascade synthetic approach is straightforward that could avoid hazardous reagents/solvents and is turned to be a benign chemistry for the preparation of potent bis‐O‐heterocyclics on a multigram scale.

Use of Dialkyl Acetylenedicarboxylates in the Multicomponent Synthesis of Heterocyclic Structures

“…), amine 42 in the presence of trifluoroacetic in EtOH as a solvent at room temperature gave the corresponding product 43 (Scheme 17). [38] The three-component reaction of cyclohexyl isocyanide 12, dialkyl acetylenedicarboxylate 1 and 1-aryl-2ene-3-acetyl-1,4diketone derivatives 44 for the synthesis of 5-cyclohexylimino-2,5-dihydrofurans 45 was reported in 2018 by Latifi et al This approach was achieved in CH 2 Cl 2 at room temperature (Scheme 18). [39] Furanone derivatives 46 were synthesized using the threecomponent reaction of aniline 2, dialkyl acetylenedicarboxlate 2, Entry 2), [40] using tetra-methylguanidine-functionalized silica-coated iron oxide magnetic nanoparticles (Fe 3 O 4 @TMG) as an efficient catalyst in ethanol (Table 2, Entry 2), [41] in the presence of Al-droped ZnO nanostructure (0.025 g) in EtOH in refluxing and under ultrasonic irradiation at 70 °C (Table 2, Entry 3), [42] and also in the presence of silicacoated magnetic nanoparticles based on acidic ionic liquid in EtOH (Table 2, Entry 4).…”

“…), amine 42 in the presence of trifluoroacetic in EtOH as a solvent at room temperature gave the corresponding product 43 (Scheme 17). [38] …”

Improved One-Pot, Four-Component Strategy to Access ­Functionalized Dihydropyridines by Using 4-(N,N-Dimethylamino)pyridine as a Catalyst

“…[12][13][14][15] 4-(N,N-Dimethylamino)pyridine (DMAP) can promote a number of organic transformations as a reusable catalyst, [16][17][18] and the combination of an MCR approach with organocatalysis has proved to be a most effective strategy. 19 In a continuation of our current work devoted to the synthesis of medicinally important heterocycles by using green solvents or catalysts, [20][21][22][23][24][25][26][27][28][29][30] R. Ramesh et al…”