Copper-catalyzed Cyclization Reaction Research Articles

Copper-Catalyzed [4+1] and [4+2] Reactions through Tandem ­Remote Propargylation/Cyclization/Isomerization with an Amine or a Hydrazine

AbstractTwo novel copper-catalyzed cyclization reactions involving a remote propargylic substitution/cyclization/isomerization cascade are disclosed. Derivatives of the seldomly studied heterocycles thieno[2,3-c]pyrrole and thieno[2,3-d]pyridazine are conveniently synthesized in moderate to good yields from primary amines or arylhydrazines through [4+1] and [4+2] reactions, respectively. Preliminary mechanistic experiments corroborated the occurrence of the designed cascade reactions.

Copper-Catalyzed Synthesis of N-Fused Quinolines via C(sp3)-H Activation-Radical Addition-Cyclization Cascade.

A novel copper-catalyzed cyclization reaction for the synthesis of pyrazolo[1,5-a]quinoline, triazolo[1,5-a]quinoline, and pyrrolo[1,2-a]quinoline derivatives is described. The process is initiated by di-tert-butyl peroxide-mediated C(sp3)-H activation to generate the α-functionalized radical, which supervenes a cascade radical addition/cyclization sequence to access the N-fused quinolines in good yields with broad functional group tolerance.

Copper-catalyzed Cyclization Reactions in Pursuit of Molecules That Inhibit DXP synthase

Copper-catalyzed Cyclization Reactions in Pursuit of Molecules That Inhibit DXP synthase

Copper-catalyzed cyclization reaction: synthesis of trifluoromethylated indolinyl ketones.

A novel, simple, effective and rapid synthetic method to construct the C-2 trifluoromethylated indolinyl ketones via a copper-catalyzed cyclization reaction between N-alkylaniline and β-(trifluoromethyl)-α,β-unsaturated enones was developed. The results of the control experiments show that the reaction may involve a radical mechanism by a single-electron transfer process. Moreover, a broad substrate scope and good functional groups, high diastereoselectivities (dr, up to >20 : 1) as well as gram-scale synthesis make this approach highly attractive.

Efficient copper-catalyzed synthesis of 2-arylbenzimidazole derivatives by reaction of 1-fluoro-2-nitrobenzene with benzamidine hydrochlorides

Figure not available: see fulltext. A novel and efficient approach to the preparation of 2-arylbenzimidazoles is described. Heating a mixture of 1-fluoro-2-nitrobenzene and benzamidine hydrochlorides in the presence of CuBr and K2CO3 in DMSO afforded 2-arylbenzimidazoles in good to excellent yields. The reaction was initiated by nucleophilic aromatic substitution and further proceeded by intramolecular nucleophilic copper-catalyzed cyclization reaction of benzamidine. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

Synthesis of a library of glucal-derived triazoles via copper-catalyzed azide–alkyne cyclization

A library of glucal-derived triazoles have been synthesized using the copper-catalyzed azide-alkyne cyclization reaction starting from 3,4,6-tri-O-acetyl-d-glucal. Different trimethylsilyl substituted alkyne derivatives of glucal were first synthesized from 3,4,6-tri-O-acetyl-d-glucal, using Sonogashira coupling, hydrostannation and iodination steps. These glucal-based trimethylsilyl-protected alkynes were then used in the copper-catalyzed cyclization reactions with different organic azides to synthesize the corresponding triazole derivatives of d-glucal.

ChemInform Abstract: Synthesis of N‐Vinylindoles Through Copper Catalyzed Cyclization Reaction of N‐(2‐Alkynylphenyl)imine.

AbstractThe copper‐catalyzed cyclization of N‐(2‐alkynylphenyl)imines (I) and (VII) leads to desired 2‐substituted N‐vinylindoles (II) and (VIII) in moderate to good yields.

Synthesis of N-vinylindoles through copper catalyzed cyclization reaction of N-(2-alkynylphenyl)imine.

A copper(II)-catalyzed cyclization reaction of N-(2-alkynylphenyl)imine was developed. This strategy provided an effective procedure for the synthesis of substituted N-vinylindoles in moderate to good yields.

Copper-catalyzed cyclization reactions for the synthesis of alkaloids

Copper-mediated Ullmann type transformations have recently evolved as useful and valuable synthetic tools in organic synthesis. If newly developed catalytic systems are readily available, inexpensive, and tolerate most functional groups, they also provide new opportunities in natural product synthesis since they allow new and efficient retrosynthetic disconnections. They are also especially convenient for the development of straightforward cyclization and macrocyclization procedures. The present article showcases some examples of copper-catalyzed cyclization reactions for the synthesis of alkaloids we have recently developed.