1,2-联烯基酮的合成与反应

1,2-联烯基酮可以通过2-丙炔基酮异构化反应,相应有机金属试剂中间体与酯、酰氯或酰胺的反应,[2,3]或[3,3]迁移反应,Wittig反应,消除反应,2,3-联烯醇氧化等方法合成。由于联烯酮上含有吸电子基团羰基,它可发生亲核加成、环加成、环化反应。     

Synthesis of heteroaryl 1,2-diketones

Reactions of lithiated heteroaryl- (or aryl-) methylbenzotriazoles 4a-e with heteroaryl (or aryl) esters 5a-f give alpha-benzotriazolyl ketones 6a-n in average yields of 90-95%. Oxidation of ketones 6a-l in aqueous DMSO in the presence of oxygen and sodium bicarbonate gave heteroaryl- (aryl-) 1,2-ethanediones 7a-l in average yields of 60-80%.     

Synthesis of chromones

A general procedure for the preparation of chromones from the boron difluoride complex of o-hydroxyaryl methyl ketones is described. One of the best methods used for the preparation of chromones and benzochromones is the treatment of o-hydroxyaryl methyl ketones with the dimethylacetal of dimethylformamide followed by treatment with sulfuric acid (1). We previously had shown (2) that benzochromone 4 was prepared in reasonable yield by the following reaction sequence.     

Synthesis of medicinally interesting polyfluoro ketones via perfluoroalkyl lithium reagents

The addition of (pentafluoroethyl)- and (heptafluoropropyl)lithium to various acyl derivatives was studied. Weinreb and morpholine amides led to polyfluoro ketones in high to quantitative yields in short reaction times. Derivatives of 2-fluorocarboxylic acids may produce 1,1,1,2,2,4-hexafluoro ketones and 1,1,1,2,2,3,3,5-octafluoro ketones. The methodology can provide inhibitors for various lipolytic enzymes, including phospholipase A2.     

A Facile Synthesis of Various Butenolides

The synthesis of α'-acyloxy-α,β-unsaturated cyclic ketones from the corresponding α,β-unsaturated cyclic ketones by using manganese (III) acetate in combination with 2-chloropropionic acid followed by subsequent Arbuzov and intramolecular Horner-Emmons cyclization reactions provided a convenient synthetic pathway to various butenolides 4a-d.     

全氟烷基芳基酮的合成

本文用8种取代苯基卤化物,在无水四氢呋喃中制成的格氏试剂与全氟羧酸(R_FCO_2H,R_F=CF_3和n-C_3F_7)按 3:1摩尔比反应,合成了9种全氟烷基芳基酮(1～9),其中6、7、8和9是新化合物。它们的结构用IR、UV、NMR(~1H,~(19)F)及MS加以表征。     

Synthesis of α-amino alcohols of the selenophene series

(2-Selenienyl)ethanolamines were synthesized by the reduction of the corresponding amino ketones and isonitroso ketones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 626–628, May, 1972.     

Synthesis and properties of polyether ketones

Polyether ketones were prepared by the nucleophilic reaction of dihaloaromatic ketones with aromatic bisphenols (hydroquinone, resorcinol and 4,4-dihydroxybenzophenone) using various solvents in the presence of anhydrous K₂CO₃. Dihaloaromatic ketones (4,4-difluorobenzophenone/4,4-dichlorobenzophenone) were prepared from the reaction of fluorobenzene/chlorobenzene with carbon tetrachloride in the form of AlCl₃. The polymers were characterized by different physico-chemical techniques. Thermogravimetric studies showed that all the polymers were stable upto 500°C with a char yield above 50% at 900°C in N₂ atmosphere. Isothermal degradation at 400°C under air and N₂ atmosphere reveals about 5% weight loss and about 1% weight loss at 75 min respectively. The effect of solvents, reaction temperature and reaction time on molecular weights are discussed. The effect of the annealing time on crystallinity of the polymers is also discussed.     

Photochemical Synthesis of Highly Functionalized Cyclopropyl Ketones

A series of di‐ and trisubstituted cyclopropyl ketones 11 were prepared by irradiation of ketones 3 and 5 , which bear a leaving group adjacent to the carbonyl C‐atom. The required ketones 3 could be easily synthesized either by functionalization of ketones 1 with a hypervalent iodine reagent, 2 , or by O‐sulfonylation of α‐hydroxy ketones 7 . The nitrates 5 were obtained by treatment of the corresponding α‐bromo ketones with AgNO₃. The irradiation of 3 and 5 must be performed in the presence of an acid scavenger (1‐methyl‐1H‐imidazole) to obtain the cyclopropanes 11 in good yields. The synthetic efficiency of the method was, among other things, demonstrated by the preparation of a highly strained bicyclo[2.1.0]pentane 11i in good yield. The mechanism of the photochemical cyclization was investigated by means of photokinetic measurements, as well as by quantum‐chemical calculations. It was shown that the presence of the leaving group substantially influences all steps of the photochemical reaction cascade. The X‐ray crystal structures of 11j and exo‐ 11k were also determined.     

Synthesis of 1,3,4,6-tetraoxo compounds

The two-step method of synthesis of 1,3,4,6-tetraoxocompounds with different terminal substituents is developed. By condensation of alkyl methyl ketones with dimethyl oxalate new 1,6-dialkyl-substituted 1,3,4,6-tetraoxohexanes are obtained. The esters of 3,4,6-trioxoalkanoic acids are synthesized by the condensation reaction of alkyl acetates with dialkyl oxalates and alkyl methyl ketones. By the reaction of ethyl acetate with diethyl oxalate and methyl acetate the mixed diester of 3,4-dioxo-1,6-hexanedioic (ketipic) acid has been first prepared. Specific structural features of the synthesized compounds are discussed basing on the data of the IR, NMR, and XRD diffraction (XRD) analysis.     

Palladium-Catalyzed Tunable Carbonylative Synthesis of Enones and Benzofulvenes

A palladium-catalyzed four-component carbonylative coupling reaction involving aryl halides, internal alkynes, arylboronic acids, and CO has been developed for the first time. All-carbon substituted α-unsaturated ketones and benzofulvenes can be selectively obtained in a highly regio- and stereocontrolled manner. Using Cu(TFA)₂ as the additive, a series of tetrasubstituted α-unsaturated ketones were prepared in moderate to high yields. Using more acidic Lewis acid Cu(OTf)₂ as the additive, multisubstituted benzofluvenes were synthesized in moderate yields. This efficient methodology involved the formation of three new C−C bonds, and provided a divergent method for the quick construction of multisubstituted α-unsaturated ketones and benzofulvenes from easily available starting materials.     

Synthesis of diaryl ketones via a phosphine-free Fukuyama reaction

The synthesis of unsymmetrical diaryl ketones via the Fukuyama coupling of thioesters and organozinc reagents is described. Typically, the synthesis of diaryl ketones using this methodology provides low yields. The simple complex, Pd(dba)(2), was found to convert a variety of aryl thioesters to diaryl ketones in good yields.     

Synthesis and some reactions of aryl 4,5-dichloroisothiazol-3-yl ketones

By acylation of benzene, toluene, and p-xylene with 4,5-dichloroisothiazole-3-carbonyl chloride the corresponding aryl 4,5-dichloroisothiazol-3-yl ketones were obtained. By reaction of 4,5-dichloroisothiasol-3-yl 4-methylphenyl ketone with piperidine, alkyl(aryl) thiolates, sodium alcoholates, and 2,4-dinitrophenylhydrazine were synthesized 4-methylphenyl 5-piperidyl-4-chloroisothiazol-3-yl ketone, 5-alkyl(aryl)sulfanyl-4-chloroisothiazol-3-yl 4-methylphenyl ketones, 5-alkoxy-4-chloroisothiazol-3-yl 4-methylphenyl ketones, and 2,4-dinitrophenylhydrazone of the initial ketone respectively.     

Synthesis of cyclic enones via direct palladium-catalyzed aerobic dehydrogenation of ketones

α,β-Unsaturated carbonyl compounds are versatile intermediates in the synthesis of pharmaceuticals and biologically active compounds. Here, we report the discovery and application of Pd(DMSO)(2)(TFA)(2) as a catalyst for direct dehydrogenation of cyclohexanones and other cyclic ketones to the corresponding enones, using O(2) as the oxidant. The substrate scope includes heterocyclic ketones and several natural-product precursors.     

Synthesis of ketones from aroyl chlorides and nickel(0) complexes

Summary Facile syntheses of ketones have been achieved starting from bis(1,5-cyclooctadiene)nickel(0) and aroyl halides containingortho-substituents. Electrophilic or nucleophilic attack of aroyl groups upon organic substrates also give rise to other classes of ketones.     

Synthesis of aromatic ketones by a transition metal-catalyzed tandem sequence

Both simple Ag(I) and Au(I) are effective catalysts for a tandem [3,3]-sigmatropic rearrangement/formal Myers-Saito cyclization of propargyl esters to form aromatic ketones. A mechanism in which the metal catalyzes both of these processes through alkyne activation is proposed. By using this method a wide range of aromatic structures including naphthyl, anthracenyl and indole ketones are available from readily available propargyl esters.     

Synthesis of alpha-hydrazino ketones via regio- and stereoselective electrophilic amination of manganese enolates and enamines

A straightforward procedure for the regio- and stereoselective synthesis of alpha-hydrazino ketones is described. Manganese enolates and manganese enamines derived from ketones and from the corresponding N-sulfinylimines react with azodicarboxylate esters (DTBAD and DEAD) in a regioselective fashion to afford in good to excellent yields the kinetic alpha-hydrazino ketones as sole or highly prevalent products. When enantiopure N-sulfinyl manganese enamines were used the stereoselectivity of these reactions ranged from 40% to 68% ee.     

Synthesis and Reactivity of 3-R-1-Adamantyl Methyl Ketones

A general procedure was proposed for synthesizing 3-R-1-adamantyl methyl ketones from the corresponding adamantanecarbonyl chlorides and dimethyl malonate in toluene (benzene) in the presence of sodium hydroxide. Intermediate dimethyl (3-R-1-adamantylcarbonyl)malonates can also be isolated. The resulting ketones were brought into reactions with hydroxylamine and formamide in the presence of formic acid to obtain the corresponding oximes and 1-(3-R-1-adamantyl)ethylamines. Dimethyl (3-R-1-adamantyl- carbonyl)malonates reacted with phenylhydrazine to give adamantyl-substituted 4,5-dihydropyrazol-5-one derivatives.     

Synthesis of polyfluorinated ketonesvia the ate-complexes

Russian Chemical Bulletin - Asymmetric polyfluorinated ketones RFCOR are formed by treating various derivatives of (polyfluoro)alkanoic acids (esters, anhydrides, acid chlorides) with lithium...     

Synthesis of diazahomoadamantanones thiosemicarbazones

Thiosemicarbazones of ketones from 3,6-diazahomoadamantane series were prepared by two procedures: by treating 3,6-diazahomoadamantan-9-ones with thiosemicarbazide and by a reaction of substituted (3,6-diazahomoadamantan-9-ylidene)hydrazines with versatile isothiocyanates.