Facile and efficient synthesis of indazole derivatives by 1,3-cycloaddition of arynes with diazo compounds and azomethine imides

N-Unsubstituted indazoles 3 and 1-arylindazoles 4 are readily available in good to high yields through [3+2] cycloaddition of 2-(trimethylsilyI)aryl triflates 1 and diazo compounds in the presence of KF or CsF under mild reaction conditions. Furthermore, we found that azomethine imides also underwent cycloaddition reaction with 2-(trimethylsilyl)phenyl triflates (la) in the presence of KF to afford indazolone derivatives 6 in moderate yields.