Cascade Synthesis of Benzimidazole-Linked Pyrroles via Copper Catalyzed Oxidative Cyclization and Ketonization
Tzuen-Yang Ye1, Manikandan Selvaraju1, Chung-Ming Sun1,2
1Department of Applied Chemistry, National Chiao-Tung University , 1001, Ta-Hseuh Road, Hsinchu 300-10, Taiwan.
Abstract:
A three-component cascade reaction of 2-aminobenzimidazole, aldehyde, and terminal alkyne has been explored for an efficient synthesis of benzimidazole-linked tetrasubstituted pyrroles. The reaction sequence involves the formation of propargylamine, insertion of a terminal alkyne, and a ring opening reaction followed by an intramolecular carbonylative cyclization under aerobic conditions. It represents a novel strategy to the construction of C═N, C═C, C═O bonds and a new five-membered 2-ketopyrrole ring. In this process, the reaction conditions are crucial and an attempt to elucidate the novel reaction pathway is well supported by X-ray crystallography.
More Related Videos
Related Concept Videos
Cycloaddition Reactions: Overview
Preparation of Epoxides
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Ketones with Nonenolizable Aromatic Aldehydes: Claisen–Schmidt Condensation
As the self-condensation of ketones is generally not favored in basic conditions, the self-condensed products do not form in the reaction between ketones and benzaldehyde. The general reaction of Claisen–Schmidt...

![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
