Nucleophilic di- and tetrafluorination of dicarbonyl compounds.
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.
Singh
R P
RP
Department of Chemistry, University of Idaho, Moscow, ID 83844-2343, USA.
Majumder
U
U
Shreeve
J M
JM