| 11559172 |
Singh RP, Majumder U, Shreeve JM: Nucleophilic di- and tetrafluorination of dicarbonyl compounds. J Org Chem. 2001 Sep 21;66(19):6263-7.
Reactions of various diketo compounds with Deoxofluor [(CH (3) OCH (2) CH (2))(2) NSF (3)] have been investigated. When reacted with Deoxofluor, alpha-diketones, R (1) COCOR (2) (R (1) = R (2) = Ph; R (1) = R (2) = 4-Me-C (6) H (4); R (1) = Ph, R (2) = Me; R (1) = Me, R (2) = Et) (1a-d) formed difluoro derivatives (2a-d) in the presence of a catalytic amount of HF and/or tetrafluoro (3a-d) products depending on the reaction conditions and stoichiometry used. Reactions of beta-diketones, R (3) COCH (2) COR (4) (R (3) = R (4) = Ph; R (3) = R (4) = Me; R (3) = Me, R (4) = Ph) (4e-g), with Deoxofluor in the presence of a catalytic amount of HF led to the formation of difluoroalkenones as a mixture of E (5e-g) and Z (6e-g) isomers in good yield. Reaction of other diones, R (5) CO-X-COR (6) (R (5) = R (6) = Ph, X = -CH=CH-; R (5) = R (6) = Me, X = -C (6) H (4) C (6) H (4)-; R (5) = R (6) = Ph, X = -CH (2) CH (2) CH (2)-; R (5) = R (6) = Me, X = -CH (2) CH (2)-) (7h-k) with Deoxofluor produced mainly difluoro products (8h-k) with low yields of tertrafluoro derivatives (9h-k). Acyclic alpha-keto amides react poorly to give the corresponding difluoro derivatives, whereas cyclic alpha-keto amides (10l-p) react smoothly under very mild conditions to produce the corresponding difluoro products (11l-p) in > 88% isolated yield. |
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