Catalyzed Domino Reaction Research Articles

Photochemical Gold Catalyzed Domino Reaction for the Synthesis of Indolines and Tetrahydroquinolines

Photochemical Gold Catalyzed Domino Reaction for the Synthesis of Indolines and Tetrahydroquinolines

Copper-catalyzed oxidative cyclization of 2-(1H-pyrrol-1-yl)aniline and alkylsilyl peroxides: a route to pyrrolo[1,2-a]quinoxalines.

An efficient method was developed for the one-pot construction of pyrrolo[1,2-a]quinoxalines via a Cu(II)-catalyzed domino reaction between 2-(1H-pyrrol-1-yl)anilines and alkylsilyl peroxides. This reaction proceeds through C-C bond cleavage and new C-C and C-N bond formation. A mechanistic study suggests that alkyl radical species participate in the cascade reaction.

A Copper-Catalyzed Interrupted Domino Reaction for the Synthesis of Fused Triazolyl Benzothiadiazine-1-oxides.

Copper(I)-catalyzed domino reactions of 2-azido sulfoximines with 1-iodoalkynes yield fused triazolyl-containing benzothiadiazine-1-oxides. The protocol features the synthesis of two fused heterocyclic rings in one step with good to excellent yields and a broad functional group tolerance. Detailed mechanistic investigations indicate that a copper π-complex initiates a cycloaddition and oxidative C-N coupling reaction sequence. The results suggest an interrupted domino process involving an iodinated triazole as a key intermediate.

Gold(I)‐Catalyzed Carbothiolation via Rearrangement of S‐Propargyl Group: An Access to 3‐Allenyl or 3‐Indenyl Benzo[b]thiophenes

AbstractA series of 3‐allenyl benzo[b]thiophenes were synthesized through a gold(I)‐catalyzed domino reaction. The process consists in a 5‐endo‐dig cyclization with C−S bond formation and consecutive S‐to‐C propargyl migration via [3,3]‐sigmatropic Claisen rearrangement. With aryl substituents on both triple bonds of the substrate, subsequent intramolecular hydroarylation on the formed allenyl system led to 3‐indenyl benzo[b]thiophenes. From a substrate bearing a 3‐butynol moiety diverse fused O‐heterocycles have been obtained via intramolecular hydroalkoxylation. A gold‐mediated 1,3‐migration involving allenyl to propargyl rearrangement is also described.magnified image

I2/FeCl3-Catalyzed Domino Reaction of Aurones with Enamino Esters for the Synthesis of Highly Functionalized Pyrroles.

A novel and efficient I2/FeCl3-catalyzed domino reaction of aurones with enamino esters via Michael addition, iodination, intramolecular nucleophilic substitution, and spiro ring opening processes has been developed, affording a vast variety of polysubstituted pyrroles in moderate to excellent yields. This protocol features mild reaction conditions, broad substrate scope, high atom economy and efficiency, and feasibility for large-scale synthesis. A plausible mechanism for the pyrrole synthesis is proposed.

Silver Triflate Catalyzed Domino Reactions of o‐Alkynylanilines: An Approach Toward Unsymmetrical Diarylacetates and Triarylmethanes

AbstractStraightforward and efficient Ag(I) catalyzed domino reactions for the synthesis of unsymmetrical diarylacetate and triarylmethane derivatives has been reported. These reactions proceed via an initial 5‐endo‐dig cyclization of o‐alkynylanilines to result in the indole motif which further reacts with various electrophiles resulting in a wide range of unsymmetrical diarylacetates, diaryl ketones, and triarylmethanes. The strategy is versatile, displays broad substrate scope, and provides excellent yields of the products.

Gold(I)‐Catalyzed Domino Reaction: An Access to Furooxepines

AbstractAbstract. We report herein the synthesis of [7,5]‐fused bicyclic acetals, also named furooxepines through a gold(I)‐catalyzed domino reaction. During this transformation, two molecules of homopropargyl alcohol react together, in a sequence including an intramolecular hydroalkoxylation, condensation, a 1,6‐enyne cycloisomerization, acetalization and an isomerization. This gold(I)‐catalyzed domino reaction allow the formation of three bonds, two heterocycles and a tetrasubstituted carbon stereocenters in a one‐step operation with 100% atom economy. Post‐functionalizations allow the formation of tetrahydrofurans.magnified image

Recyclable Amberlite IR-120 Catalyzed domino reaction: Synthesis, anticancer activity and molecular docking studies of biscoumarins

Under mild conditions, an environmentally friendly method has been developed for the synthesis of bis-coumarins by using a reasonably lesser quantity of Amberlite IR-120 through Domino Knoevenagel–Michael reaction. In which, a series of aryl aldehydes have efficiently reacted with 4-hydroxycoumarin to give respective bis-coumarins through a short reaction time. The acidic Amberlite IR-120 catalyst used for a reaction was isolated and reused for successive four reactions. As per the observations made, the activity of the recycled catalyst was preserved. The invitro examination of bis-coumarins against two cancer cell lines was proved that, some of these have showed promising anti-proliferative properties. The molecular docking studies of bis-coumarin derivatives with GlcN-6-P synthase yielded potential conformations with prospective binding energy, docking energy, inhibition constant and electrostatic energy while comparing with the standard drug chloroquine.

Ytterbium(III) triflate catalyzed domino reaction of arylamines and styrene oxides: Synthesis of 2-benzyl-3-arylquinoline derivatives

An efficient and straightforward method for the synthesis of 2-benzyl-3-arylquinoline derivatives is reported involving the domino reaction of substituted arylamines and styrene oxides in the presence of 10 mol% ytterbium(III) triflate in acetonitrile at 80 °C. Additionally, the reaction of aliphatic epoxides with p-anisidine provided 2,3-dialkylquinoline derivatives under identical reaction conditions. Important features of the protocol are ease of handling, broad substrate scope, good yields, and the formation of two CN and two CC bonds.

Synthesis of substituted anilines via a gold-catalyzed three-component reaction.

A three-component reaction for the synthesis of substituted anilines by a gold(i)-catalyzed domino reaction was developed. Cationic gold catalysts selectively and sequentially activated two different alkynes, which were involved in pyrrole synthesis and subsequent Diels-Alder reaction. The sequential formal (3 + 2) annulation/Diels-Alder reaction of three components provided a variety of substituted anilines in a modular fashion. Moreover, utility of the aniline products was demonstrated by derivatization to substituted benzoxazines, which are pharmaceutically important heterocycles.

Mechanistic understanding of the Cu(i)-catalyzed domino reaction constructing 1-aryl-1,2,3-triazole from electron-rich aryl bromide, alkyne, and sodium azide: a DFT study

The mechanism of the Cu(i)-catalyzed domino reaction furnishing 1-aryl-1,2,3-triazole assisted by CuI and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is explored with density functional theory (DFT) calculations.

Gold(I)-Catalyzed Domino Reaction for Furopyrans Synthesis.

We report herein an efficient synthesis of furopyran derivatives through a gold(I)-catalyzed domino reaction. The cascade reaction starts with two regioselective cyclizations, a 5-endo-dig and a 8-endo-dig, followed with a Grob-type fragmentation and a hetero Diels–Alder. The obtained furopyran derivatives contain fused and spiro-heterocycles. During this one-pot process, four bonds and four controlled stereogenic centers including a quaternary center are formed.

Solvent Effect in Gold(I)-Catalyzed Domino Reaction: Access to Furopyrans.

We report an efficient synthesis of furopyrans through a gold(I)-catalyzed domino reaction. By starting from the same source and changing the solvent of the reaction, two classes of furopyrans are accessible. During this one-step process, which takes place in DMF, two bonds and two heterocycles are formed. DFT calculations furnish the mechanistic understanding of this transformation. The sequence includes a 5-endo-dig cyclization, a regioselective 8-endo-dig cyclization, and a retro 8π and a 6π electrocyclization.

Synthesis and In Vitro Cytotoxicity and Antibacterial Activity of Novel 1,2,3-Triazol-5-yl-phosphonates.

Novel 1,2,3-triazol-5-yl-phosphonates were prepared by the copper(I)-catalyzed domino reaction of phenylacetylene, organic azides and dialkyl phosphites. The process was optimized on the synthesis of the dibutyl (1-benzyl-4-phenyl-1H-1,2,3-triazol-5-yl)phosphonate in respect of the catalyst, the base and the solvent, as well as of the reaction parameters (molar ratio of the starting materials, atmosphere, temperature and reaction time). The method elaborated could be applied to a range of organic azides and dialkyl phosphites, which confirmed the large scope and the functional group tolerance. The in vitro cytotoxicity on different cell lines and the antibacterial activity of the synthesized 1,2,3-triazol-5-yl-phosphonates was explored. According to the IC50 values determined, only modest antibacterial effect was detected, while some derivatives showed moderate activity against human promyelocytic leukemia HL-60 cells.

Ag(PcL)]‐Catalyzed Domino Reactions of 2‐Alkynylbenzaldehydes with Electron‐Poor Anilines: Synthesis of 1‐Aminoisochromenes

In this paper, we describe the synthesis of neglected 1‐aminoisochromene derivatives starting from 2‐alkynylbenzaldehydes and electron‐poor anilines. The domino reaction is catalyzed by original [AgIPcL] complexes and occurs with complete regioselectivity under mild conditions. The approach well‐tolerates different aryl, heteroaryl, alkyl and cycloalkyl substituents on alkyne terminus to give the desired products in modest to very good yields.

Copper(II)‐catalyzed Domino Reaction of the Acyclic Ketene‐(S,S)‐Acetals with Diazo Compounds: Convenient Synthesis of Poly‐substituted Thiophenes

AbstractCopper(II)‐catalyzed domino reaction between the acyclic ketene‐(S,S)‐acetals and diazo compounds has been successfully developed. This reaction proceeds through a sequential formation of electrophilic copper carbenoid, sulfur ylide and subsequent C−S bond coupling and cleavage. Notably, the domino reaction features broad the readily available acyclic ketene‐(S,S)‐acetals scope and provides a new strategy for the synthesis of poly‐substituted thiophenes.magnified image

Palladium‐Catalyzed Synthesis of 6H‐Dibenzo[c,h]chromenes and 5,6‐Dihydrobenzo[c]phenanthridines: Application to the Synthesis of Dibenzo[c,h]chromene‐6‐ones, Benzo[c]phenanthridines, and Arnottin I

Abstract6H‐Dibenzo[c,h]chromenes and 5,6‐dihydrobenzo[c]phenanthridines have been synthesized via Palladium (II)‐catalyzed domino reactions of acetylenic substrates involving intramolecular trans‐oxo/amino palladation onto the triple bond followed by nucleophilic addition of the intermediate to a tethered cyano/aldehyde. The scope of this reaction was extended through one step conversion of some of the products to 6H‐dibenzo[c,h]chromen‐6‐ones and benzo[c]phenanthridines. Utilization of this methodology led to a formal total synthesis of the natural product Arnottin I.magnified image

Intramolecular α-Oxygenation of Amines via N -Heterocyclic Carbene-Catalyzed Domino Reaction of Aryl Aldehyde: Experiment and DFT Calculation

We have developed an N-heterocyclic carbene (NHC)-catalyzed domino reaction with aryl aldehyde through a simple acyl azolium intermediate using phenyliodine(III) diacetate (PIDA) as an oxidant. Con...

Functionalization of Oxazolo[4,5‐b]pyrazines by Deprotometallation

Different 2‐arylated oxazolo[4,5‐b]pyrazines, obtained by palladium(II)‐catalyzed domino reaction from 2,3‐dichloropyrazine and the corresponding carboxamides, were functionalized by deprotometallation. Employing lithium 2,2,6,6‐tetramethylpiperidine, in order to form a lithio derivative, and then trapping it by iodolysis, proved to be inefficient. However, the presence of a zinc‐based in situ trap allowed most substrates to be functionalized. Deprotonation of the pyrazine ring was observed in the presence of tolyl and anisyl groups at the oxazole 2‐position. In contrast, with chlorophenyl and thienyl groups in this 2‐position, deprotonation rather occurred on these groups either competitively or exclusively. The regioselectivities were discussed in the light of calculated pKa values of the substrates in THF. Finally, in the case of 2‐phenyloxazolo[4,5‐b]pyrazine, we converted the mixture of 5‐ and 6‐iodinated products into the corresponding 5,6‐diiodide, which was further functionalized by a double Suzuki coupling.

Asymmetric Synthesis of Cyclopentene-Fused Tetrahydroquinolines via N-Heterocyclic Carbene Catalyzed Domino Reactions

A new strategy for the N-heterocyclic carbene catalyzed asymmetric synthesis of cyclopentene-fused tetrahydroquinoline derivatives has been developed. The one-pot organocatalytic domino protocol allows a direct entry to the characteristic cyclopenta[c]tetrahydroquinoline core of many alkaloids and some potential drugs employing readily available quinolinone and enal substrates in good domino yields and stereoselectivities.