Thallium(III) p‐tosylate‐mediated oxidative [1,2] rearrangement of 2‐naphthyl and 2‐heteroarylchromanones

A practical and effective approach towards the synthesis of 3‐heteroaryl‐4H‐chromen‐4‐ones by the oxidative [1,2] rearrangement of the respective 2‐heteroaryl chroman‐4‐ones using thallium(III) p‐tosylate is presented. The oxidative rearrangement of α‐ and β‐naphthyl and thiophene substituents behaves like aryl groups; However, pyridyl substituents gave only dehydrogenated products. A practical and effective approach towards the synthesis of 3‐heteroaryl‐4H‐chromen‐4‐ones by the oxidative [1,2] rearrangement of the respective 2‐heteroaryl chroman‐4‐ones using thallium(III) p‐tosylate is presented. The oxidative rearrangement of α‐ and β‐naphthyl and thiophene behaves like aryl groups; However, pyridyl substituents gave only dehydrogenated products.