Patent ID: 6815563
Filing Date: 2004-11-09
Classification: C07C

Abstract:
A process for preparing bicyclic 1,3-diketones of the formula I whereR1, R2, R3 and R4 are hydrogen, C1-C4-alkyl, C1-C4-alkoxycarbonyl, halogen, cyano, nitro, C1-C4-alkylthio, C1-C4-alkylsulfenyl or C1-C4-alkylsulfonyl and Z is C1-C4-alkylene, O, S, Nâ€”R5 where R5 is C1-C4-alkyl or C1-C4-alkylcarbonyl, which comprises a) reacting a bicyclic olefin of the formula II with haloform in the presence of a base to give the ring-expanded product of the formula III â€ƒwhere R1-R4 and Z are as defined above and X is halogen; b) hydrolyzing the allylic halogen of the compound of the formula III to the allyl alcohol of the formula IV c) oxidizing the allyl alcohol of the formula IV to the unsaturated ketone of the formula V d) reacting the ketone of the formula V with a nucleophilic ion Yâˆ’ which stabilizes a negative charge to give the ketone of the formula VI â€ƒwherein Y is the nucleophilic group of the nucleophilic ion Yâˆ’, e) hydrolyzing the ketone of the formula VI to the bicyclic 1,3-diketone of the formula I.