Synthesis of catechols from cyclohexanones via acid-regulated dual oxidative transformations with TEMPO†

Herein, we disclosed a metal-free, operationally simple, general method for the straightforward synthesis of catechols via an α-oxygenation of cyclohexanone-initiated cascade oxidative reaction sequence. This metal-free method was particularly advantageous for the synthesis of pharmaceutically relevant catechols, as it eliminated the need for costly and potentially toxic metal catalysts. An exhibition of more than 60 cyclohexanone substrates proved the reliability of this protocol in directly synthesizing structurally diverse and synthetically useful bioactive molecules, which are conventionally unattainable by existing methods.