29981-98-4

Upstream product

• 201230-82-2 carbon monoxide 
• 134856-38-5 N-(3-buten-1-yl)-1,2-phenylenediamine 
• 108413-26-9 1-(but-3-en-1-yl)-1H-benzo[d]imidazole 
• 88-73-3 2-Chloronitrobenzene 
• 150649-19-7 2-(1-methylcyclopropyl)-1H-benzimidazole 
• 54624-57-6 2-bromo-1H-1,3-benzodiazole 
• 134856-55-6 N-(but-3-enyl)-2-nitrobenzenamine 
• 51-17-2 benzoimidazole 

Relevant academic research and scientific papers

Switchable Regioselective 6-endo or 5-exo Radical Cyclization via Photoredox Catalysis

Controlling the regioselectivity of radical cyclizations to favor the 6-endo mode over its kinetically preferred 5-exo counterpart is difficult without introducing substrate prefunctionalization. To address this challenge, we have developed a simple method for reagent controlled regioselective radical cyclization of halogenated N-heterocycles onto pendant olefins. Radical generation occurs under mild photoredox conditions with control of the regioselectivity governed by the rate of hydrogen atom transfer (HAT). Utilizing a polarity-matched thiol-based HAT agent promotes the highly selective formation of the 5-exo cyclization product. Conversely, limiting the solubility of the HAT reagent Hantzsch ester (HEH) leads to selective formation of the thermodynamically favored 6-endo product. This occurs through an initial 5-exo cyclization, with the resulting alkyl radical intermediate undergoing neophyl rearrangement to form the 6-endo product. Development of this switchable catalysis strategy allows for two modes of divergent reactivity to form either the 6-endo or 5-exo product, generating fused N-heteroaromatic/saturated ring systems.

Construction of All-Carbon Quaternary Stereocenters by Scandium-Catalyzed Intramolecular C-H Alkylation of Imidazoles with 1,1-Disubstituted Alkenes

The exo-selective C-H cycloaddition of imidazoles to 1,1-disubstituted alkenes has been achieved for the first time by using half-sandwich scandium catalysts. A wide range of imidazole compounds bearing various 1,1-disubstituted aliphatic alkenes, styrenes, dienes, and enynes have been selectively converted in high yields to the corresponding bicyclic imidazole derivatives bearing β-all-carbon-substituted quaternary stereocenters. By using a chiral half-sandwich scandium catalyst, the asymmetric exo-selective cyclization has also been achieved with a high level of enantioselectivity.

Enantioselective Ni-Al Bimetallic Catalyzed exo -Selective C-H Cyclization of Imidazoles with Alkenes

A Ni-Al bimetallic catalyzed enantioselective C-H exo-selective cyclization of imidazoles with alkenes has been developed. A series of bi- or polycyclic imidazoles with β-stereocenter were obtained in up to 98% yield and >99% ee. The bifunctional SPO ligand-promoted bimetallic catalysis proved to be critical to this challenging stereocontrol.

Synthesis of 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazoles via the cyclopropyliminium rearrangement of substituted 2-cyclopropylbenzimidazoles

2-Cyclopropylbenzimidazole derivatives with various substituents in the small ring undergo cyclopropyliminium rearrangement into 2,3- dihydropyrrolobenzimidazoles substituted at positions 1, 2 or 3. The substrates containing a functional group in position 1 of the cyclopropane ring form products substituted at position 3. Substituents at position 2 in most cases lead to the formation of a mixture of isomers. The reaction can be directed to yield one of the isomers predominantly by varying the solvent polarity.

Microwave-assisted C-H bond activation: A rapid entry into functionalized heterocycles

(Matrix presented) Microwave irradiation strongly accelerates the rhodium-catalyzed intramolecular coupling of a benzimidazole C-H bond to pendant alkenes. The cyclic products were formed in moderate to excellent yields with reaction times less than 20 min. Additionally, the use of microwave irradiation allowed the reactions to be performed without any solvent purification and with minimal precautions to exclude air.

Synthesis of Benzimidazoles Containing a Fused Alicyclic Ring By Rhodium - Catalysed Hydroformylation of N-Alkenyl-1,2-diaminobenzenes

Rhodium-catalysed reactions of N-alkenyl-1,2-diaminobenzenes (3) with hydrogen and carbon monoxide give benzimidazoles containing a fused alicyclic ring ((8) and (9)) in excellent yields.In some cases intermediate bicyclic compounds can be isolated and the 1H and 13C n.m.r. spectra of one of these, the 3,4,5,6-tetrahydro-4-methyl-3H-1,6-benzodiazocine (6), shows evidence for unusual atropisomerism.

A metal catalysed route to benzimidazoles containing a fused alicyclic ring

Rhodium catalysed reactions of N-alkenyl-1,2-diaminobenzenes (1) with hydrogen and carbon monoxide give benzimidazoles containing a fused alicyclic ring (6,7) in excellent yields.