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The ability of Selectfluor to act as a nucleofuge for hydrolysis of beta-anti-halides was investigated with N-alkoxycarbonyl derivatives of 6-anti-Y-7-anti-X-2-azabicyclo[2.2.1]heptanes and 4-anti-Y-8-anti-X-6-azabicyclo[3.2.1]octanes. The azabicycles contained X = I or Br groups in the methano bridge and Y = F, Br, Cl, or OH substituents in the larger bridge. The relative reactivities of the halides were a function of the azabicycle, the halide, and its bridge and the addition of Selectfluor or HgF(2) as a nucleofuge. All halide displacements occurred with retention of stereochemistry. Selectfluor with sodium bromide or sodium chloride, but not sodium iodide, competitively oxidized some haloalcohols to haloketones. A significant 15.6 Hz F...HO NMR coupling was observed with 4-anti-fluoro-8-anti-hydroxy-6-azabicyclo[3.2.1]octane.

Successive alkylation of 5-(3-phenylthioureido)-3H-imidazole-4-carboxamides with alkyl halides and chloroacetone gave (N-oxopropylimidazolyl)isothioureas, which were easily converted into derivatives of purine and imidazopyrazinone. In the case of ethyl 5-(3-phenylthioureido)-3H-imidazole-4-carboxylate, primary alkylation occurs at the N atom of the imidazole ring. Reactions of 5-(3-phenylthioureido)-3H-imidazole-4-carboxamides with haloketones afforded a number of 4-hydroxy-2-imidazolyliminothiazolidines and 2-imidazolylimino-Δ4-thiazolines.

Carbon-14 labeled 4-[4-[2-[2-[bis(4-chlorophenyl)methoxyethylsulfonyl] [1-14C]ethoxy]phenyl]-1,1,1-trifluoro-2-butanone was prepared in a six step radioactive synthesis from 2-bromo[1-14C]acetic acid. The overall radiochemical yield was 2.2%. The specific activity of the final product was found to be 42μCi/mg with a radiochemical purity of >98%. Copyright © 2002 John Wiley & Sons, Ltd.

The Dakin-West reaction of N-alkoxycarbonyl-N-alkyl-alpha-amino acids (1a-j) with trifluoroacetic anhydride in the presence of pyridine gave alpha-amido trifluoromethyl ketones (2a-j), in which probable intermediates were mesoionic 1,3-oxazolium-5-olates (munchnones). The diastereoselective reduction of 2a-f with NaBH4 gave the threo-aminoalcohols (5a-f), which may be explained by the Felkin-Anh model. This was confirmed by converting 5a-f into trans-5-trifluoromethyl-2-oxazolidinones (6a-f) in good yields.

A novel pathway for the preparation of 3, 4-dihydro-2H-1λ6-benzo[e][1, 2]thiazine 1, 1-dioxides 3 via an orthomethyl lithiation/cyclization reaction of N-acyl-o-toluenesulfonamides 5 is reported. Readily available N-acyl-o-toluenesulfonamides 5 were treated with 2 eq of n-BuLi at -78°C-0°C to give the corresponding sultams 6 in moderate to good yields. The resulting sultams 6 were converted to saturated sultams 3, which can be considered as one carbon-extended homologues of the Oppolzer sultams 1, in high yields by hydrogenation. Studies on the scope and limitation of this annulation for the preparation of sultams are discussed. Demonstration of the feasibility of using the sultams 3 templates for an electorophilic fluorinating agent is also described.

The π values of benzalacetones (BZ) and trans-1, 1, 1-trifluoro-4-phenyl-3-buten-2-ones (TF) with a substituent on the benzene ring were analyzed by the directional Hommett-type treatment. The correlation equation showed that πBZ and πTF values are altered from the π value of monosubstituted benzenes, πPhX, mainly by the change in the hydrogen bonding behavior of the variable substituent caused by the electron-withdrawing fixed substituent. The log k' values for BZ and TF derived from reversed-phase liquid chromatography (RPLC) were correlated with log P values determined by using different compositions of methanol-phosphate buffer (pH 7.4) as eluents. A good linear correlation was obtained at 50% methanol concentration.

The pK a values of the freely water-soluble opened form of a thieno-1,2,4-triazolo-1,4-diazepine, namely 2-(3-amino- methyl-5-methyl-1,2,4-triazolo)-3-(2-chlorobenzoyl)- [2,3-c]thienopiperidine, were determined. pH measurements were made in the range 1 < pH < 10. Two of the three pK a values found in this range significantly overlapped; they quantify the ionization of both the aminomethyl residue and the piperidino moiety of the molecule. The third corresponds exclusively to the ionization of the triazolo nucleus. The pK a value of the thienophenone was obtained by UV spectrophotometry using acidity functions. All results were extracted from experimental data by a curve-fitting method.

The Friedel-Crafts acylation of 1-acetylindoline with (S)-2- or (R)-2-(methanesulfonyloxy)propionyl chloride, and aluminum chloride in dichloromethane at room temperature did not afford the expected (S)- or (R)-1-acetyl-5-[2-(methanesulfonyloxy)propionyl]indoline, but gave optically pure (R)- or (S)-1-acetyl-5-(2-chloropropionyl)indoline, whose stereochemistry at the asymmetric carbon was inverted during the reaction. Similar reaction of 1-acetylindoline with the same chiral acylating agents in the presence of aluminum bromide gave mainly the corresponding 2-bromopropionyl derivatives, but as stereo mixtures.

Aromatic aldehydes or ketones which have electron-withdrawing groups on the benzene ring were selectively reduced to the corresponding alcohols in good yields by sodium hydrogentelluride; common aldehydes such as benzaldehyde and tolualdehyde were inert.

An efficient synthetic method for 3-aryl-5-butyl-4-oxazolin-2-ones (6) is described. The reaction of ethyl N-arylcarbamates (10) with 1-bromo-3, 3-dimethyl-2-butanone (9a) or 1-bromo-3-ethyl-3-methyl-2-pentanone (9b) using 2.2 eq of lithium bis(trimethylsilyl)amide afforded 6 in good yields. The reaction mechanisms are discussed.

A series of optically active substituted 1,2-dihydro-6-oxo-pyrrolo[3,2,1-ij]quinoline-5-carboxylic acids was prepared via optically active 2-methyl-4,5-difluoroindoline (10) and tested for antibacterial activities. Among them, (2S)-9-[(3R,1'S)-3-(1'-amino)ethyl-1-pyrrolidinyl]-8-fluoro-1,2-dihydro- 2- methyl-6-oxo-6H-pyrrolo[3,2,1-ij]-quinoline-5-carboxylic acid (19) showed potent activity against gram-positive bacteria and (2S)-8-fluoro-1,2-dihydro-2-methyl-9-(3-methyl-1-piperazinyl)-6-oxo-6H- pyrrolo[3,2,1-ij]quinoline-5-carboxylic acid (16) exhibited well balanced in vitro activity, good intravenous efficacy, and high aqueous solubility.

Chiral bis(alpha, alpha-diphenyl-2-pyrrolidinemethanol) carbonate (DPP(2).H(2)CO(3)) is a useful asymmetric auxiliary for the asymmetric borane reduction of prochiral ketones. Chiral DPP(2).H(2)CO(3) is recoverable from the reaction and directly reusable for the reaction. The intermediate of KUR-1246, which we are developing as a new uterine relaxant, was synthesized using the methodology.

This article contains brief overviews, mechanisms and practical details for organic synthesis named reactions and processes beginning with the letter ‘F’. Reactions included in this section are: FAVORSKI α-Haloketone Rearrangement; FEIST–BENARY Furan Synthesis; FELDMAN Vinylcyclopentane Synthesis; FELKIN Ene Mg Cyclization; FERINGA–PFALTZ Asymmetric Michael Addition; FERRARIO–AKERMANN Thiocyclization; FERRIER Carbohydrate Rearrangement; FERRIER Chiral Cyclohexenone Synthesis; FINEGAN Tetrazole Synthesis; FINKELSTEIN Halide Displacement; FISCHER Carbene Complexes; FISCHER lndole Synthesis; FISCHER Oxazole Synthesis; FITTIG Pinacolone Rearrangement; FLEMING–MAH Anthracene Synthesis; FLOOD Silyl Chloride Synthesis; FOKIN Cu Catalyzed Triazole Synthesis (“Click”); FORSTER Diazo Synthesis; FORSTER–DECKER Amine Synthesis; FRANCHIMOND Cyano Succinic Acid Synthesis; FRANKEL–SHIBASAKI Allylamine Rearrangement; FRANKLAND Organometal Synthesis; FREEMAN Lithium Reagent; FREUND–GUSTAVSON Cyclopropane Synthesis; FREUNDERBERG–SCHONBERG Thiophenol Synthesis; FRIEDEL–CRAFTS Alkylation Acylation; FRIEDLANDER Quinoline Synthesis; FRIES Phenol Ester Rearrangement; FRITSCH–BUTTENBERG–WIECHELL Acetylene Synthesis; FUJIMOTO–BELLEAU Cyclohexenone Synthesis; FUJIWARA Arylation Carboxylation; FUJIWARA Lanthanide (Yb) Reaction; FUKUYAMA Thioester Coupling; FŰRSTNER Fe Catalyzed C C Coupling

Sonication of a zinc/copper couple, N,O-bis(trimethylsilyl)-acetamide (BSA) and α,α'-oligobromo ketones in benzene gives rise to oxyallyl intermediates which cycloadd to anthracene. Starting from 1,1,3,3-tetrabromoacetone (2a) and anthracene (1a), we obtained 11,11,13-tribrominated adduct 4 as the major product (42%). The expected 11,13-dibrominated adduct trans-3 was formed as a minor product (5%), but it became the main product when the known oxyallyl methodology was applied. Dibenzohomobarrelenes 9 and 17 were prepared by short routes.

The syn and anti isomers of 2-fluoro-2-(trifluoromethyl)-3-hydroxy ketones are reduced in a highly 1,2-syn diastereoselective manner with lithium aluminum hydride or diisobutylaluminum hydride in tetrahydrofuran at −78 °C, affording 1,2- syn -2,3- syn - and 1,2- syn -2,3- anti -2-fluoro-2-(trifluoromethyl)-1,3-diols, respectively, in excellent yields. High 1,2-syn stereoselectivity in the reduction can be ascribed to the presence of the 2-trifluoromethyl substituent.

The selective bromination with copper(II) bromide of the pyrrole ring in 2-(2'-hydroxybenzoyl)pyrrole (II) in the heterogeneous phase is des- cribed giving in almost quantitative yield the 4,5-dibromo derivative (VI). The subsequent introduction of halogen into the phenol moiety was observed when the reaction was perfomed in the homogeneous phase with an excess of halogenating agent. The pentabromo derivative (IX), a com- pound very active against Staphylococcus aureus (mic=17 nmoles per dm -3 ), was obtained by exhaustive bromination of the title compound. Poor yields of chloro derivatives of (II) were obtained by reaction of the parent compound with copper(II) chloride

A systematic study of the asymmetric reduction of aryl and alkyl α-fluoroalkyl ketones with (−)-diisopinocampheylchloroborane ((−)-DIP-Chloride, 1 ), and (−)- B -isopinocampheyl-9-borabicyclo[3.3.1]nonane ( R -Alpine-Borane, 2 ) has been made. In the case of reagent 1 , the direction of asymmetric induction in the chiral reduction of aryl trifluoromethyl ketones differs from that of the corresponding mono- and difluoromethyl ketones. For example, while 2-fluoro, and 2,2-difluoroacetophenones are reduced with 1 to the R -alcohols in 95% and 85% ee, respectively, 2,2,2-trifluoroacetophenone is reduced, under neat conditions at room temperature, to the S -alcohol in 90% ee. Though DIP-Chloride reduces unhindered prochiral dialkyl ketones in poor ee, alkyl α-fluoroalkyl ketones are reduced in improved ee depending on the number of α-fluorine atoms present in the ketone. While monofluoromethyl ketones provide moderate ee in the R -isomer, the di- and trifluoromethyl ketones are reduced in moderate to excellent ee in the opposite isomer. For example, 1-fluoro-2-octanone is reduced in 40% ee ( R ), whereas 1,1-difluoro- and 1,1,1-trifluoro-2-octanone are reduced in 32% ( S ), and 91% ee ( S ), respectively. In the case of the asymmetric reduction of the above series of ketones with 2 , the results are different. There is no change in the direction of chiral induction in the reduction of α-fluoroacetophenones with 2 . 2-Fluoroacetophenone and 2,2-difluoroacetophenone are reduced with 2 to the R -alcohol in 89% and 97% ee, respectively. The reaction of 2,2,2-trifluoroacetophenone is very slow, only 90% complete in 45 d, and provides the R -alcohol in 32% ee. In contrast, while 1-fluoro- and 1,1-difluoro-2-octanone are reduced by 2 in 65% ( R ) and 50% ee ( R ), respectively, 1,1,1-trifluoro-2-octanone is reduced in 60% ee ( S ), raising the question of which factors other than the steric size of the trifluoromethyl group, control the enantioselectivity of these reductions. The effect of steric versus electronic influence in such chiral reductions is discussed.

The title rearrangement is shown to proceed at ca. 100 °C to afford the γ,δ-unsaturated perfluoroalkyl ketones. The stereochemistry of the Wittig and Claisen processes and the effect of the Rf-group in the Claisen process are discussed.

Principal Component Analysis (PCA) was carried out on the basis of property descriptors for a set of α-halogenated ketones and aldehydes. The obtained PCA model showed that the chemical behaviour of the compounds with 1-ethoxy-3-trimethylsilylprop-1-yne is related to the steric effect of the structural environment of the C=O group. Moreover the PCA model, the steric effect was underlined quantitatively with regression analysis models.

The preparation of hitherto unknown trifluoromethyl substituted 2-amino-3,4,6-triarylbenzophenones 3 by a 2,5-[C4+C2] rins transformation of 2,4,6-triarylpyrylium salts 1 with trifluoromethylbenzyl cyanides 2 in the presence of sodium methanolate in methanol is reported. Spectroscopic data of the benzophenones 3 and the mode of their formation are discussed.

A versatile synthetic method for preparing 1-substituted 3-nitroquinolin-4(1H)-ones from corresponding 2-fluoro-α-nitroacetophenones is demonstrated by the synthesis of 6,7-difluoro derivatives 7a-c. The method involves sequential treatment of the starting nitroacetophenone with triethyl orthoformate and the appropriate amine, followed by a nucleophilic cyclization reaction under mild conditions. The C-7 fluorine atom of 7 can be displaced by cyclic amines. Substituted 6-fluoro-7-(4-methyl-1-piperazinyl)-3-nitroquinolin-4(1H)-ones 8a-c were prepared in this way.

A series of β-alkyl-α,β-unsaturated trifluoromethyl ketones have been prepared from the corresponding α-acetylenic trifluoromethyl ketones. The addition of sulfur nucleophiles was shown by chemical and 19 F NMR studies to proceed exclusively by 1,4-addition with no indication of any 1,2-addition products. The unsaturated trifluoromethyl ketones have been shown to be effective inhibitors of rat cytosolic glutathione-S-transferase

Conformation and Bromination of Bicyclo[3.3.1]nonane-2,6-dione and Dehydrobromination of the Bromo Ketones. – Improved Synthesis of Bicyclo[3.3.1]nona-3,7-diene-2,6-dione Bromination by copper(II) bromide of bicyclo[3.3.1]nonane-2,6-dione (1) affords the epimeric α-bromo diketones exo-and endo-5 and, eventually, the α, α′-dibromo diketones exo- and endo-7 (3:7) in high yield. Dehydrobromination of the mixtures of bromo diketones by calcium carbonate in dimethylacetamide yields the unsaturated diketones 6 (30%) and 2 (72%), respectively. Bromination of 1 by molecular bromine is less selective and furnishes mixtures of brominated diketones consisting of exo- and endo-7, 8 and the tetrabromo diketone 10. An excess of bromine yields pure 10. – The ethylene acetal 12 is brominated by pyridinium perbromide to produce the α,α′-dibromo acetal 13 which is very reluctant towards 1,2-dehydrobromination by potassium tert-butoxide. Thus, with an excess of potassium tert-butoxide in tetrahydrofuran, 1,2-dehydrobromination is achieved only on one side to afford 14. In contrast, potassium tert-butoxide in dimethyl sulphoxide induces a transannular dehydrobromination leading to the diacetal 15 of 3-bromonoradamantane-2,6-dione. – The conformations of 1,10, and 13 in the solid state are determined by X-ray diffraction analyses. From torsional angles, vicinal proton coupling constants are calculated with the aid of the Karplus equation and compared to those determined from solutions by high-field NMR spectroscopy. The reasonable agreement provides the basis for the assessment of the configuration and conformation for exo- and endo-7.

On controlled heating to 100 o C, 3-chloro-3-cyclobutene-1,2-diones (5a) reacted with 1,1'-bi-1-cyclohexenyl (6) and 1,1'-bi-1-cyclopentenyl (13) to give the dicycloalkano-annulated dihydrobenzocyclobutenediones 7 and 16, respectively. Treatment of carbon tetrachloride solutions of 7 and 16 with bromine at reflux temperature afforded the corresponding benzocyclobutenediones 9 and 17. Surprisingly, the reaction of 5a with 1,1'-bi-1-cycloheptenyl (14) and 1,1'-bi-1-cyclooctenyl (15) gave directly the benzocyclobutenediones 20 and 21. The hitherto unknown 3-bromo-3-cyclobutene-1,2-dione (5c) was prepared by treatment of 3-hydroxy-3-cyclobutene-1,2-dione (5b) with oxalic dibromide in 76% yield. Its reaction with the dienes 6, 13, 14 has been investigated

exo-7-Chloro-endo-7-phenylbicyclo[3.2.0]hept-2-en-6-one (5) undergoes cine substitution reactions with methoxide anions and with dialkylamines to give 5-methoxy or 5-dialkylamino derivatives 13, 14, 16–19 in high yield. While attempts directed to an acetalization have failed, the addition of Grignard reagents to the methoxy derivatives proceeds stereoselectively in high yield. Hydrochlorides 20/21 lose amine at 110°C to form 2-phenyltropone (22). Thermolysis of diethylamino derivative 24 at 170°C (temperature determined by DSC) results in the formation of the dienaminone 25.

The reactions of 3,6-dibromo-2,7-dioxotetracyclo[6.3.0.0 4,11 .0 5,9 ]undecane with organomagnesium halides are investigated as a method of preparing unusual tetrasubstituted pentacycloundecanes (D 3 -trishomocubanes). The tetrasubstituted pentacycloundecanes have been characterized and product geometries confirmed by NMR and X-ray crystal structure analysis. Rel-(1R,2R,3S,4S,5R,6R,7S,8S,9R,10R)-4-hydroxy-4-phenyl-6-methyl-7-bromo-(D 3 )-trishomocubane ( 11 ) exhibits a sterically locked phenyl group with a rotation barrier > 17 kcal/mol which should make possible the preparation of stable rotational isomers with o- or m-substituted phenyl groups.

Fluorination of allyl β-keto car☐ylates using N-fluoro-2,4,6-pyridinium triflate gave allyl α-fluoro-β-keto car☐ylates. Reaction of allyl α-fluoro-β-keto car☐ylates with formic acid in the presence of palladium-phosphine catalyst gave α-fluoro ketones. When the palladium-catalyzed reaction was carried out without formic acid, the decar☐ylation-allylation took place to give α-fluoro-allylketones. Decar☐ylation-dehydrogenation to afford α-fluoro-α,β-unsaturated ketones was carried out with palladium catalysts in acetonitrile.

Asymmetric bromination of chalcone and benzylideneacetone ( trans -isomers) in crystalline β-cyclodextrin complex was studied. While bromination of chalcone in the absence of β-cyclodextrin yields erythro -dibromide, bromination of β-cyclodextrin-chalcone complex results in the formation of a mixture of erythro - and threo -dibromides respectively in the ratio 80:20. Complexation does not induce any variation in the bromination pattern in the case of trans -benzylideneacetone. These observations have been accounted for in terms of different conformations of the enones in the β-cyclodextrin-enone complexes. Complex formation between the substrate and cyclodextrin has been confirmed by various physical methods.

Enolised α-thiocyanato-β-dicarbonyl compounds dimerise in ethanol at room temperature to give tautomeric 4,5-disubstituted 2-amino- and 2-acetamido-thiazoles by a C-S-C + C-N cyclisation. Tautomerism is due to the unusual 4-(β-dicarbonyl-α-thio) substituent. Competing intramolecular cyclisations lead to minor amounts of heterocycles containing the thiazole and/or oxathiole ring systems

Methylthio-substituted allenylmethylsilane, a kind of allylsilane, undergoes only [2 + 2] cycloaddition reaction with alkenes mediated by a Lewis acid to afford the corresponding methylenecyclobutanes which are readily converted to di-exo-methylenecyclobutanes by the sequential oxidation-1,2-elimination in good yield. Di-exo-methylenecyclobutane is also successfully applied to construct a bicyclo[5.2.0]nonenone skeleton by the reaction with 2-oxyallyl cation.

A convenient approach to aryl 3-pyridazinyl ketones (4), (7-10) bearing various O-, N-, or C-substituents at C-6 of the diazine nucleus via oxidative decyanation of appropriate aryl-heteroaryl- acetonitriles is proposed

α-Perfluorosulfatoperfluorocarbonyl compounds interact with alkaline metals halogenides to form the corresponding α-halo derivatives as a result of the direct nucleophilic substitution of the FSO 3 group. Through the action of halogenide anions on perfluorinated α,β-bis-fluorosulfatocarbonyl compounds, substitution by halogen of the FSO 3 group in the α-position to the carbonyl takes place. However, the FSO 3 group in the β-position is cleaved, which allows α-substituted β-dicarbonyl derivatives to be obtained.

Fluorination of α,α-dichloro- F -2-ketones with antimony pentafluoride provided excellent yields of α-chloro- F -2- ketones and F -2-ketones regioselectively. However, fluorination of α,α-dibromo- F -2-ketones with antimony pentafluoride gave a mixture of α-bromo- F -2-ketones and F -2-ketones.

The reaction of dialkyl phosphonates with chloroacetone and base under phase-transfer catalyst conditions has been investigated. Dialkyl 1,2-epoxyalkylphosphonates are obtained in good yield from the reaction. A two-step mechanism involving deprotonation of the dialkyl phosphonate, followed by nucleophilic attack by the phosphonate anion at the carbonyl group of the ketone is proposed. The oxirane formation during the second stage of the reaction involves displacement of chloride ion. The reaction is highly selective.

4,4'-Bi(cyclobutene-1,2-diones), novel compounds derived from squaric acid, here named bisquaryls, were prepared for the first time either by the palladium-catalyzed oxidative dimerization of (tri-n-butylstannyl)cyclobutene-1,2-diones (providing symmetrically substituted bisquaryls) or by a palladium-copper cocatalyzed cross-coupling of 3-substituted-4-(tri-n-butylstannyl)-3-cyclobutene-1,2-diones with 3-halo-4-substituted-3-cyclobutene-1,2-diones (providing a route to unsymmetrically substituted bisquaryls). The novel parent bisquaric acid is a very strong BrOnsted acid that apparently fully ionizes on dissolution; only one pK a value (pK a = -4.49) was observed

Ru(II)- or Cu(I)-induced radical reaction of CF 2 ClCCl 2 . radical (2), regioselectively derived from CF 2 ClCCl 3 , to trimethylsilyl enol ethers and a ketene silyl acetal yields (β,β,γ-trichloro-γ,γ-difluoropropyl)carbonyl compounds 5 as the intermediates. Spontaneous dehydrochlorination affords [β-chloro-β-(chlorodifluoromethyl)vinyl]carbonyl compounds 4. Reductive dechlorination of 4 with zinc gave γ,γ-difluoroallyl ketones 7a-e and an ester 7f. In some cases, Ni(O)-catalyzed reduction with zinc is superior than the simple hydrodechlorination

Treatment of 3,3,3-trifluoropropynyl-lithium ( 4 ) with benzil (2:1 molar ratio) in diethyl ether at −50 °C, followed by addition of an excess of benzoyl chloride, affords 1-benzoyl-5-benzoyloxy-5-phenyl-2,3-bis(trifluoromethyl)cyclopenta-1,3-diene ( 11 ) (61%) and the 1,4-dialkynyl ester (CF 3 CC) 2 CPhO 2 CPh ( 1b ) (8%). Similar reaction of the salt 4 with α-chloroacetophenone (2:1 molar ratio) in diethyl ether at −50 °C, followed by addition of a slight excess of benzoyl chloride, gives the ester CF 3 CCPh(CH 2 Cl)O 2 CPh ( 14a ) (55%) and a compound considered to be 2,5-diphenyl-2,5-bis(3,3,3-trifluoropropynyl)-1,4-dioxan ( 15 ) (30%). Under the same conditions, α-bromoacetophenone yields the corresponding bromo ester CF 3 CCCPh(CH 2 Br)O 2 CPh ( 14b ) (39%), 2-phenyl-2-(3,3,3-trifluoropropynyl)oxirane ( 16 ) (25%) and the dialkynyl ester ( 1b ) (7%). The oxirane 16 , conveniently prepared (51%) by treatment of salt 4 with the bromoketone (1:1 molar ratio) in THF at −60 °C, on reaction with lithium phenylacetylide followed by addition of benzoyl chloride ( c . 1:1:1 molar ratio) in THF at −60 °C gives a compound identified as 2-phenyl-2-(1-phenyl-5,5,5-trifluoropent-3-en-1-yn-3-yl)oxirane ( 17 ) or possibly 2-phenyl-2-(3-phenylprop-2-yn-1-yl)-3-(2,2,2-trifluoroethylidene)oxirane ( 18 ) in 28% yield.

Reaction of a—haloketones with aldehydes in the presence of either SmI3 or Sm/I2 formed the carboncarbon double bond to give α,β—unsaturated ketones in good to excellent yields under mild conditions. Samarium ( III ) enolates formed from the dehalogenation of α—haloketones by SmI3 were assumed to be the reaction intermediates.

In the reaction of N,N′-dimethyl thiourea, 1 with n-butyl lithium, followed by some dichlorophosphorus(III) compounds, in the presence of triethylamine the phosphadiazetidine thiones, 2-5 were obtained. In contrast to the analogous urea derivatives dynamic behavior was observed in the room temperature 1H and 13C n.m.r. spectra of 2-5. Oxidation reactions at the λ3P atom of 2 are described, involving as oxidizing agents bis(trimethylsilyl)peroxide (→6), elemental sulfur (→7), tetrachloro-o-benzoquinone (TOB) (→9), and phenyl azide (→10). An unusual reaction with hexafluoroacetone (HFA) was observed for the dimethylamino-substituted diazadiphosphetidine thione, 2: two molecules of HFA were oxidatively added to the λ3P atom, producing a perfluoropinacolyl ring system, while a further molecule of HFA was inserted into a PN bond of the diazadiphosphetidine thione ring system.

The endocyclic replacement of a nitrogen atom at the 1-position of quinolone antibacterial nucleus with a sulfur atom was investigated. A series of 1-benzothiopyran-4-one-3-carboxylic acids 14-16 and isothiazolo[5,4-b][1]benzothiopyran-3,4-diones 22-24, suitably functionalized with a fluorine atom at C-6 and heterocyclic base at C-7, were prepared. The antibacterial evaluation of the target compounds showed an activity comparable to that of nalidixic acid for compounds 14-16, while an increased activity against gram-positive bacteria was observed for compounds 22-24

(tert1-Butylisonitrile)copper(I) Complexes with Acetylacetonato-or η51-Cyclopentadienyl Ligands Copper(I) complexes of the type acacCu(CNtBu) (1) and CpCu(CNtBu) (2) are accessible by the reaction of [ClCu-(CNtBu)]4 with M(β1-diket) or MCp (MLi, Na, K, Tl), respectively. hfacCu(CNtBu)2 (3) and hfacCu(CNtBu)3 (4) are prepared by adding molar amounts of tBuNC to hfacCu(CNtBu) (1b).

The reaction of iododifluoromethyl ketones with alkenes catalyzed by Pd(PPh 3 ) 4 in the absence of solvent at room temperature gives high yields of the corresponding 1:1 addition products. Treatment of the adducts with Zn/NiCl 2 ·6H 2 O/THF affords α,α-difluoroketones. A variety of functional groups in the olefins are tolerated under the reaction conditions, including alkyl, trimethylsilyl, hydroxy, epoxy, carbonyl and ester groups.

Treatment of the complex [W(CO)(NCMe)(S 2 CNC 4 H 8 ) (η 2 -MeC 2 Me) 2 ][BF 4 ] with an equimolar quantity of M(LL){M(LL)  Na[S 2 CNMe 2 ]·2H 2 O, Na[S 2 CNEt 2 ]·3H 2 O, Na[S 2 CN(CH 2 Ph) 2 ], [NH 4 ]S 2 CNC 4 H 8 ], K[S 2 COEt], Na[OC(CH 3 )CHCO(CH 3 )], Na[OC(CF 3 )CHCO(CF 3 )] or Na[OC(Ph)CHCO(CH 3 )]} at room temperature in CH 2 Cl 2 affords good yields of the new neutral mixed-ligand complexes [W(CO)(LL)(S 2 CNC 4 H 8 )(η 2 -MeC 2 Me)] ( 1 - 8 ). 13 C NMR spectroscopy indicates that the but-2-yne is acting as a four-electron donor in these complexes.

Intramolecular Barbier reactions, initiated with lithium or magnesium metals, were carried out on a model compound 3 and afforded four products, including the cyclic product 6 and cyclopropane-containing product 7. Single and double electron transfer sequences are proposed to explain their formation.

1,3,2λ5σ5-Dioxaphospholanes have been obtained from trifluoromethylphosphonous aciddiethyl ester, the corresponding bis(diethyldiamide), (Z)-1,2,3,3,3-pentafluoropropenyl-phosphonous acid diethyl ester and hexafluoroacetone. (Z)-1,2,3,3,3-Pentafluoropropenylphosphonousacid bis(diethylamide) furnished, unexpectedly, 2-bis(diethylamino)-2,3-difluoro-4,5,5-tris(trifluoromethyl)-1,2λ5σ5-oxaphospholene-(3). The structures of the twoCF3 group-containing dioxaphospholanes were confirmed by single-crystal X-ray investigationsand shown to exhibit distorted trigonal bipyramids with CF3 occupying the axialposition.

Tin enolates 1 reacted with α-halogeno ketones 2 and esters 10 to give a variety of 1,4-diketones 3 and γ-keto esters 11, respectively, in the presence of appropriate additives such as hexamethylphosphoric triamide (HMPT), tributylphosphine oxide and tetrabutylammonium bromide, while complexation of these additives with tributyltin bromide allowed catalytic production of β-keto oxiranes 4 instead of 3. The reaction mechanism for the preparation of 1,4-diketone 3 is discussed.

Palladium catalyzed carbonylative cross-coupling of 4-chloro-2,3-disubstituted-2-cyclobutenones with alkenyl-, aryl-, and heteroaryltin reagents and thermolysis provides a general method for the synthesis of 2,3,6-trisubstituted-2-pyrones. The reaction is regiospecific, coupling occurring preferentially at the 4-position of the cyclobutenone.

Ambident anions [CH2COC(X)Me2]–, on collisional activation in the gas phase, could, in principle, undergo cyclisations through (i) C– to form a Favorskii cyclopropanone ion complex, or (ii) O– to form an allene oxide ion complex. No Favorskii intermediates are detected, but allene oxide ion complexes are formed when X = OMe or SMe. These cyclisation reactions are endothermic and would not be expected to occur should lower energy reaction channels be available. Such a scenario pertains when X = OH, i.e. no internal cyclisation occurs for ambident enolate [CH2COC(OH)Me2]– following collisional activation. Instead, proton transfer produces the alkoxide [MeCOC(O–)Me2] which undergoes the acyloin rearrangement (to equilibrate the three methyl groups by 1,2-methyl anion migration) prior to decomposition.

Reactions of electron-poor α-haloketones with (N-isocyanimino) triphenylphosphorane in the presence of aromatic carboxylic acids proceed smoothly at room temperature and in neutral conditions to afford disubstituted 1,3,4-oxadiazole derivatives in high yields. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:368–372, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20626