One possibility is to employ diazonium tetrafluoroborates in arene solvent together with a phase-transfer catalyst, another is to use 1-aryl-3,3-dialkyltriazenes.
A potential approach involves using diazonium tetrafluoroborates dissolved in an arene solvent with the aid of a phase-transfer catalyst, or alternatively employing 1-aryl-3,3-dialkyltriazenes.