Scalable Synthesis of Benzotriazoles via [3+2] Cycloaddition of Azides and Arynes in Flow

A method for the metal-free synthesis of benzotriazoles in flow is reported. Using azides and in situ generated arynes, benzotriazoles are formed in a [3+2] cycloaddition within minutes. Employing different substitution patterns of the azide and aryne coupling partners, a modular access to benzotriazoles is provided. Thermal strain of hazardous azides and accumulation of reactive intermediates is minimized by short reaction times in flow, improving the safety profile of the process. The scalability of the reaction is demonstrated.

Automated summary

A metal-free synthesis method for benzotriazoles in flow using azides and in situ generated arynes is reported. The modular access to benzotriazoles is provided by employing different substitution patterns of the azide and aryne coupling partners. The safety profile of the process is improved by minimizing thermal strain of hazardous azides and accumulation of reactive intermediates through short reaction times in flow. The scalability of the reaction is also demonstrated.