The [Sn(salen)](2+) complex moiety has been immobilized into NaY zeolite by in situ synthesis of the salen complex in NaY matrix to prepare a new catalyst, Sn(salen)-NaY. The catalyst has been characterized by UV-vis, infrared (IR) spectroscopy, X-ray powder diffraction. Mossbauer and Sn-119 NMR spectroscopy. The catalyst shows impressive catalytic performance (with high selectivity) in Baeyer-Villiger oxidation of various cyclic ketones including 2-adamantanone, cyclohexanone, cyclopentanone, 4-methylcyclohexanone, 2-methylcyclohexanone using tert-butyl hydroperoxide (tert-BuOOH) as an oxidant. The yield of epsilon-caprolactone from catalytic oxidation of cyclohexanone over Sn(salen)-NaY catalyst was ca. 75%. The catalyst can be recycled for several times without any major decline in catalytic activity. (C) 2010 Elsevier B.V. All rights reserved.