M.-P. Jouannetaud

Nucleophilic para-fluorination of 4-alkylphenols by hypervalent iodine reagent and pyridinium polyhydrogen fluoride (PPHF) : a novel route to 4-fluorocyclohexa-2,5-dienones

Abstract Ipso-fluorination of 4-alkylphenols with C 6 H 5 -I(OCOCF 3 ) 2 -pyridinium polyhydrogen fluoride (PPHF) yields 4—fluorocyclohexa-2,5-dienones.

Synthesis of hydroindolenones and hydroquinolenones by hypervalent iodine oxidation of mono or bicyclic phenols

Abstract Methoxy or fluoro hydroindolenones and hydroquinolenones can be obtained by oxidation of the corresponding 4-substituted open-chain phenolds with C 6 H 5 I(OCOCF 3 ) 2 with methanol or pyridinium polyhydrogen fluoride followed by an intramolecular conjugate addition. The corresponding cyclo 2,5-hexadienones can be obtained directly by a similar oxidation of the bicyclic phenols.

Fluorination in superacids: a novel access to biologically active compounds

Abstract In HF-SbF 5 , reaction of various alkaloids with NBS, NCS, H 2 O 2 yields fluoroderivatives: anti-addition is observed at the C6C7 double bond with tabersonine, but a more complex reaction is operative with vindoline, leading to 7-substituted (Br, Cl, OH)-20-fluoro derivatives. A completely different reaction pathway is observed with bis indole alkaloids (vinblastine, anhydrovinblastine, vinorelbine) in HF-SbF 5 . In the presence of NBS (or better of CCl 4 or CHCl 3 ), 20′,20′-difluoroderivatives are obtained. Vinflunine (20′,20′-difluoro-3′,4′-dihydrovinorelbine) has been selected for its promising antitumor activity.

Fluorination or hydroxylation of non activated CH bonds in amides and ketones using CCl4 or NBS in superacids

Abstract Amides and ketones are fluorinated or hydroxylated in HF-SbF5 in the presence of CCl4 or NBS, reaction occurring at a carbon far located from the functional group.

Synthesis of fluorohydrins and of bromofluoroderivatives by anti addition on the 14,15 double bond of tabersonine in superacids

Abstract Reaction of tabersonine 1a with H2O2 in HF-SbF5 yields fluorohydrins 2(22%), 3(36%) and 4(21%). In similar conditions 1a reacts with Br2 (0.6 equivalent) to give compounds 7(27%), 8(14%) ard 9(41%). These results imply addition of the electrophile H3O2+ and Br2 (“OH+” and “Br+” equivalent respectively) on the α or β face of the C-14-C-15 double bond to yield onium ions 12α or 12 β. Trapping of these ions by a fluoride ion accounts for the stereospecific formation of the anti addition products. P]Assignment of the chemical shift of every carbon has been carried out in the new compounds using, if necessary, COSY 13C-1H to remove any ambiguity.

Synthesis of gem-difluoroamines from allylic or halogenoamines

Abstract In HF–SbF5, in the presence of N-bromosuccinimide, allylic or halogenoamines yield gem-difluoroamines, through bromofluorointermediates.

Direct bromination or hydroxylation at C-11 in vincadifformine and tabersonine derivatives in superacids

Abstract In HF-SbF5, vincadifformine 1b reacts with H2O2 to yield a mixture (60%) of hydroxyderivatives 1c and 1d. 2,16-Dihydrovincadifformine 2a is more selectively hydroxylated at C-11 to give 2b (40%); in a similar reaction, 2d yields 2e (37%). Reaction of 2a with Br2 in HF-SbF5 gives regioselectively compound 2c (80%).

Synthesis of atropoisomeric fluorocyclohexadienones by ipso-fluorination of binaphthol derivatives

Nucleophilic para-fluorination of (R,S)-1,1′-Bi-5,6,7,8-tetrahydro-2-naphthol (and its monoacetate) with C6H5J(OCOCF3)2− pyridinium polyhydrogen fluoride yields atropoisomeric fluorocyclohexadienones.

Ipso-chlorination of 4-alkylphenols ethers a novel route to 4-chlorocyclohexa-2,5-dienones.

Abstract Selective chlorination of 4-alkylphenols ethers with SbF5/CH2Cl2 (CHCl3, CCl4) yields 4-chlorocyclohexa-2,5-dienones; no α-chlorination to a carbonyl group is observed in the reaction conditions.

Hydroxylation de l'estrone et de son acétate par le peroxyde d'hydrogène en milieu superacide

Abstract Estrone 1a and its acetate 1b react with hydrogen peroxide in SbF5-HF to give hydroxylated compounds. The formation of the dienone 2 can be accounted for by reaction of the electrophile H3O2+ on the neutral substrate, whereas formation of compound 3b implies electrophilic attack on the protonated ester 1b. Higher acidity favours rearrangement of the resulting ion 9 to yield, through a spiro intermediate, the ester 4b. Under the reaction conditions esters 3b and 4b]are slowly converted into the corresponding phenols 3a and 4a.