Reductive cyclization of d-keto nitriles R1COCR2R3CH2CH2CN [R1 = Me, R2 = H, R3 = H, C1-C3 alkyl, PhCH2; R1 = Ph, R2 = H, Me, R3 = Me, Et, R1R2 = (CH2)3, (CH2)4, CHMe(CH2)3, R3 = H] in the presence of TiCl4 and Zn in THF-10% aqueous Na2CO3 afforded cyclopentanones I. Similar treatment of MeCOCMe(CH2CH2CN)2 gave bicyclooctanedione II, whereas PhCOCH(CH2CH2CN)2 gave I (R1 = Ph, R2 = H, R3 = CH2CH2CONH2).

Key words: TITANIUM, REDUCTION, CYCLIZATION, PIMELIC DINITRILE, CYCLOPENTANONE