9-Methylen-8-oxo

This regioselectivity is practically not influenced by the nature of subsituent R. 3,5-Disubstituted isoxazolines are the sole or main products in [3 + 2] cycloaddition reactions of nitrile oxides with various monosubstituted ethylenes such as allylbenzene (99), methyl acrylate (105), acrylonitrile (105, 168), vinyl acetate (168) and diethyl vinylphosphonate (169). This is also the case for phenyl vinyl selenide (170), though subsequent oxidation—elimination leads to 3-substituted isoxazoles in a one-pot, two-step transformation. 1,1-Disubstituted ethylenes such as 2-methylene-1 -phenyl-1,3-butanedione, 2-methylene-1,3-diphenyl- 1,3-propa-nedione, 2-methylene-3-oxo-3-phenylpropanoates (171), 2-methylene-1,3-dichlo-ropropane, 2-methylenepropane-l,3-diol (172) and l,l-bis(diethoxyphosphoryl) ethylene (173) give the corresponding 3-R-5,5-disubstituted 4,5-dihydrooxazoles. 

C4H,3 ch3 2-(Acetoxy-methyl)-2-nitro- 3-oxo-nonan 80 2-Methylen-3-oxo-nonan 85... 

In the course of these investigations Hoffmann and his group have also developed novel entries to f-butyl 2-methylene-3-oxoalkanoates 2-109a and 2-methylene-3-oxo-sulfones 2-109b by oxidation of 2-108a and 2-108b, respectively obtained by reaction of the aldehydes 2-106 and acrylate 2-107 a or phenyl vinyl sulfone 2-107 b. The cycloadditions of these oxabutadienes to enol ethers and alkenes proceeded in the expected way (Fig. 2-29) [133]. 

To a solution of imine (65 mg, 0.25 mmol), 2Sa (15 mg, 0.025 mmol), and benzoic acid (0.15 mg, 0.0125 mmol) in dichloromethane (1.0 ml) was added MVK (42 ml, 0.5 mmol) at room temperature. Then reaction mixture was stirred at room temperature for 10 h. After the reaction completed, the solvent was removed under reduced pressure and the residue was purified by a flash column chromatography (SiO2, eluent EtOAc/petroleum ether = 1/5) to afford 4 methyl N (2 methylene 3 oxo 1 phenylbutyl) benzenesulfonamide as a color less solid. 

In the alternative approach.the 1,3-dipolar system can be constructed in several ways. Treatment of a-chloroacylhydrazones of diaryl ketones and certain aralkyl and dialkyl ketones (382) with NaH in anhydrous THF gives l-(disubstituted methylene)-3-oxo-l,2-diazetidinium inner salts (383). Reaction of (383) with DMAD in methylene chloride gave (384), a 2 1 adduct with loss of CO. Double bond migration in (384) occurred on heating to give (385). The intermediate in the cycloaddition was found to be (386), which on heating lost CO to form a new ylide system which in turn underwent reaction with more DMAD <81JA7743). 

Die Addition von Dialkylaminen an cyclische a-Methylen-ketone (z. B. 2-Methylen-l-oxo-tetralin und 3-Methylen-2-oxo-bicyclo[2.2.1]heptan) kann an Aluminiumoxid als Kata-lysator durchgefuhrt werden4 ... 

Isatogens (1) and indolones (2) are brightly colored solids that do not occur naturally. Isatogens (I) are more comprehensively named as 3-oxo-3//-indole 1-oxides, or as the 1-oxides of indolones (2), 3-oxo-3H-indoles, or 3//-indol-3-ones. Both series of compounds are numbered in accordance with IUPAC rules. Isatogens were first reported in 18811,2 and the first indolone in 1912.3 Isatogens (1), indolones (2) and indoxyls (3) form an interrelated redox system. Indolones in which there is a methylene or methine substituent in the 2-position tautomerize to the preferred 2-methylene-3//-indol-3-one (indogenide) structures (4).4 Only passing reference will be made to 3 and 4 in this review. 

By interaction of 7-amino-8-oxo-3-vinyl-5-thia-l-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid 4-methoxyphenyl ester with 4-bromoacetyl bromide was prepared 7-(4-bromo-3-oxo-butyrylamino)-8-oxo-3-vinyl-5-thia-l-azabicyclo (4.2.0)oct-2-ene-2-carboxylic acid 4-methoxyphenyl ester. The active methylene group in that product was then nitrosated with sodium nitrite. The initial product spontaneously tautomerizes to afford 7-(4-bromo-2-hydroxyimino-3-oxo-butyrylamino)-8-oxo-3-vinyl-5-thia-l-azabicyclo(4.2.0) oct-2-ene-2-carboxylic acid 4-methoxyphenyl ester. By the reaction of that compound with thiourea and then with trifluoroacetic acid was obtained (6R,7R)-7-(2-(2-amino-4-thiazolyl)glyoxylamido)-8-oxo-3-vinyl-5-thia-l-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid sodium nitrite, (Z)-oxime (Cefdinir sodium nitrile). 

METHYLENE KETONES AND ALDEHYDES BY SIMPLE, DIRECT METHYLENE TRANSFER 2-METHYLENE-1-OXO-l, 2,3,4-TETRAHYDRONAPHTHALENE... 

Methylene-1-oxo-1,2,3,4-tetrahydro-naphthalene l(2//)-Naph-thalenone, 3,4-dihydro-2-methylene- (8,9) (13203-73-1) N-Methylanilinium trifluoroacetate Aniline, A-methyl-, trifluo-roacetate (8) Benzenamine, /V-methyl-, trifluoroacetate (9) (29885-95-8)... 

Gras JL (1990) Methylene Ketones and Aldehydes by Simple, Direct Methylene Transfer 2-Methylene-l-oxo-l,2,3,4-tetrahydronaphthalene. In Organic Synthesis, Coll VII., p. 332. Wiley, New York, Chichester, Brisbane, Toronto, Singapore... 

Hexen l-Dimethylamino-3-oxo-E15/1, 660 (Dehydr.) Hydroxylamin N- 2-[l(bzw.3)-Cyclohexenyl]-ethyl - E16a, 26 Morpholin 2-Methylen-3,3,4-trimethyl- VI/4, 528 Nitron... 

Cyclohex adien 4-Brom-6-cyan-methylen-2-methoxy-3-oxo-VII/3b, 473 lodol... 

Oxa-bicyclo[3.3.0 octan 4-(Iod-trimethylsilyl-methylen)-3-oxo-E19a, 924 (radik. Cyclisierung)... 

Bicyclo 4.3.0 iionan 1-Methoxycar-bonyl- -8-methylene-2-oxo-E21c, 3015 [2-COOR —3-oxo — cyclohexen +... 

Bicyclo 2.2.1)heptan 2-Acetoxy-2-(2,5-dioxo-tetrahydrofuran-3-yl)-E19a, 804(R —HgX + En) E21c, 2221 (Hydrazon - OAc/R) Bicyclo 3.2.1 octan 5-Acetoxy-l-methoxycarbonyl-6-methylen-3-oxo- EI9a, 989 (Cyclisierung intra)... 

Benzyloxy-methyl)-1 -(2-carboxy-ethyl)-l-methyl- 1977 2-[(3-Carboxy-2-propinyloxy)-cyclo-hexyl-methyl]-l-methylen- 2285 2-(2-Ethoxycarbonyl-ethenyl)-1-(2-methyl-3-oxo-1 -cyclohexenyl)-2602... 

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