28566-14-5

The general procedure for the synthesis of 6,7-dihydrocyclopenta[b]pyridin-5-one using 2,3-cyclopentenopyridine as starting material was as follows: 0.883 mg of Mn(OTf)2 (0.5 mol%), 60 mg of 2,3-cyclopentenopyridine, 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 system was stirred in air at room temperature for 24 hours. Upon completion of the reaction, the reaction mixture was extracted with ethyl acetate (3 × 5 mL), the organic phases were combined and dried over anhydrous sodium sulfate. After filtration, the solvent was removed by distillation under reduced pressure. The crude product was purified by silica gel column chromatography using petroleum ether and ethyl acetate (5:1, v/v) as eluent to afford 60.5 mg of 6,7-dihydro-5H-cyclopentadieno[b]pyridin-5-one as a light yellow solid in 91% yield.

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