Synthesis of non-symmetric ortho-functionalized azoarenes through arylation of arylazo sulfones

Abstract

A novel protocol for the arylation of arylazo sulfones with organomagnesiums for accessing non-symmetric ortho-functionalized azoarenes has been succesfully developped. Bench-stable substituted arylazo sulfones, which serve as masked electrophilic diazo sources, have been effectively arylated, achieving good to excellent isolated yields. This method demonstrates broad tolerance towards a wide variety of substituents. Further, the mechanism and the regioselectivity of the addition has been investigated using DFT calculations. The observed regioselectivity would arise from a combination of steric and electronic effects, as well as the presence or absence of a strongly coordinating substituent at the ortho position of the arylazo sulfone.