The general procedure for the synthesis of 5,6,7,8-tetrahydroquinolin-5-one from 5,6,7,8-tetrahydroquinoline was as follows: 0.883 mg of Mn(OTf)2 (0.5 mol%), 67 mg of 5,6,7,8-tetrahydroquinoline, 0.35 g of 65% aqueous TBHP and 2.5 mL of water were added sequentially to 25 mL of a round bottomed flask. The reaction mixture was stirred in air at room temperature for 24 hours. Upon completion of the reaction, the reaction solution was extracted with ethyl acetate (3 x 5 mL), the organic phases were combined and dried over anhydrous sodium sulfate. After filtration, the solvent was removed by concentration under reduced pressure. The crude product was purified by silica gel column chromatography using petroleum ether with ethyl acetate (5:1, v/v) as eluent to afford the target compound 5,6,7,8-tetrahydroquinolin-5-one (56.6 mg, 77% yield) as a pale yellow liquid.
