Synthesis of 6,7-dihydro-5H-cyclopenta[b]pyridin-5-one analogues through manganese-catalyzed oxidation of the CH2 adjacent to pyridine moiety in water.

Direct oxidation of 2,3-cyclopentenopyridine analogues to 6,7-dihydro-5H-cyclopenta[b]pyridin-5-one analogues was achieved using Mn(OTf)₂ as a catalyst and t-BuOOH (65% in H₂O) as an oxidant at 25 °C in H₂O with high yield and excellent chemoselectivity for the first time. The catalytic system was also used efficiently for the direct oxidation of substituted benzylpyridines and 2-ethylpyridine in t-BuOH. [ABSTRACT FROM AUTHOR]