Radical

Medicinal chemistry

Composite material

Catalysis

Organic chemistry

Chemistry

Materials science

Radical cyclization

Isocyanide

Tandem

Cycloaddition

Annulation

Photochemistry

Hydrogen atom abstraction

Organic Letters

A novel access to 2-substituted benzoimidazoles, through unprecedented denitrogenative imidoyl radical cyclization of 1-azido-2-isocyanoarenes, has been developed. This tandem radical process was initiated by adding a C- or P-centered radical to isocyanide, followed by cycloaddition of the imidoyl radical to the azido group. Then, nitrogen loss and hydrogen abstraction of the resulting aminyl radical from surroundings delivered 2-substituted benzoimidazoles. Carbon radicals generated from another annulation process could also be applied, furnishing various heterocycle linked benzoimidazole derivatives.

Denitrogenative Imidoyl Radical Cyclization: Synthesis of 2-Substituted Benzoimidazoles from 1-Azido-2-isocyanoarenes