Ketones, 2-ethenyl

The reaction of the enamines of cyclohexanones with a,ft-unsaluraled sulfones gives mixtures resulting from attack of the enamine at the a- and /(-carbons of the oc,/ -unsaturated sulfone. The ratio of x- and /1-adducts is dependent upon the reaction solvent, the geometry and structure of the sulfone1 4. The diastereoselectivity of these reactions is also poor. The reaction of lithium enolates of cyclic ketones with ( )-[2-(methylsulfonyl)ethenyl]benzene, however, gives bicyclic alcohols, as single diastereomers, that result from initial -attack on the oc,/ -unsaturated sulfone5. 

Photolysis of trans-2-phenyl-3-benzoylthietane yields both cis- and trans-l,3-diphenyl-2-ethenyl ketone and polymeric thioformaldehyde instead of the anticipated thiophene derivative. 

A related approach exploited a A-cyanomethyl group to serve in the dual role of a nitrogen protecting group and a latent precursor of the formaldehyde im-inium ion (e.g., 478), and this innovative modification in tactics resulted in a simplified route to the c/.v-3a-aryloctahydroindole 474 (203a,c). To this end, the amino ketone 482 was readily prepared in one step by the reaction of 1,2-bis(trimethylsilyloxy)cyclopentene with A -benzyl-A -cyanomethyl amine. When 482 was exposed to [l-(3,4-methylenedioxyphenyl)ethenyl]lithium, a mixture (1 14) of 483 and 484 was obtained. It is noteworthy that the stereochemical sense... 

A 69.5 g portion of l-ethoxy-2-(4-pyridinyl)ethenyl methyl ketone was dissolved in 300 ml of ethanol and to the solution was added 13.2 g of malononitrile. The resulting mixture was refluxed for 5 hours, crystals starting to separate after about 30 min of refluxing. The reaction mixture was allowed to cool to room temperature and, the precipitate of fine needles was filtered, washed with ethanol and dried in a vacuum at 90°C to yield 25.4 g of 1,2-dihydro-6-methyl-2-oxo-5-(4-pyridinyl)-nicotinonitrile, m.p. >300°C. Concentration of the mother liquor provided another 2.1 g of product, m.p. >300°C. 

A further example of the use of 2//-thiopyrans as surrogates for m-substituted dienes involves the use of the protected 3,4-dihydio-3-(3-oxobutyl)A//-thiopyranA-onc, 3-[2-(2-methyl-l,3-dioxolan-2-yl)ethyl]-4-[tris(l-methy-lethyl)silyl)oxy-2//-thiopyran 328 as an equivalent of l-ethenyl-2-methylcyclohexene in Diels-Alder reactions. The thiopyran reacted with various maleimides to yield the endo cycloadducts and with methyl propenoate to give the exo adduct under either thermal or Lewis-acid-catalyzed conditions. In the latter case concomitant release of the protected ketone functions occurs, acid-catalyzed cyclization of which generates a fused cyclohexenone ring (Scheme 67). Desulfurization, preferably before the aldol cyclization, leads to derivatives of 2,3,4,4a,5,6,7,8-octahy-dro-4a-methylnaphthalenes < 1997CJC681 >. 

By the catalysis of GaCl3 and 2,6-di(/-butyl)-4-methylpyridine, five- or six- membered-ring ct,a -disubstituted ketones are ethenylated at the cr-carbon with trimethylsilylethyne at 180 °G. The roles of the base are believed to inhibit decomposition of the products and to promote photodegallation of the organogallium intermediates (Scheme 140).429... 

Arenetellurolates, ethenetellurolates, and alkanetellurolates prepared by reduction of diorgano ditellurium compounds with sodium borohydride in ethanol, THF/ethanol, or DMSO add to acetylenes in regioselective and iran.y-stereoselcctive reactions to produce aryl ethenyl tellurium products either predominantly or exclusively as (Z)-isomers. The yields are almost always higher than 70%. In reactions with acetylenic aldehydes, ketones, carboxylic acids, and esters the arenetellurolate becomes bonded to the carbon atom in a [i-position to the carbonyl group. 

The proton on the ethenyl-CH group in ethenyl phenyl tellurium is replaced by lithium upon treatment with lithium dialkylamides in THF or diethyl ether at temperatures between — 20° and — 70". The 1-lithio-l-ethenyl phenyl tellurium reacted with deuterium oxide, benzaldehyde, and diphenyl ketone as expected1. 

The methyl 2-(l//-pyrrol-2-yl)ethenyl ethers 1269, derived from enyne-imines and Fischer carbene complexes, were unstable with respect to air oxidation and were hydrolyzed to the corresponding ketones 1270 for characterization purposes (Equation 278) <20030L2043>. 

Ethyl-isopropenyl- IV/2, 375 Ethenyl-isopropyl- Vl/ld, 147 f. Furan 2-Methyl-tetrahydro- IV/lh, 157 (Cycl.) IV/ld, 226 (Keton-Red.) VI/lb, 611 f. (Jeger-Reakt) VI/3, 529f. (Cyctokond.) Oxetan... 

Sulfonsaure Trifluormethan- (2-cyclopropyl-1 -methyl-ethenyl-ester) Ell, 1089 [(R —S02)20 -(-Keton]... 

Hydrazin l,l-Dimethyl-2-(2-methoxycarbonyl-l-methyl-ethenyl)- E15/1, 758 (Keton + R2N-NH2)... 

Dimethoxy-methylen)- VII/4, 345 1 -Hydroxy-( 1 -methoxy-ethenyl)-E15/1, 209 (Enol-ether + R-Li/ Keton)... 

Oxa-spiro[4.5]decan VI/3, 533 l-Oxa-spiro[2.5]octan 2,2-Dimethyl-E19d, 865 (Br -> Li/ + Keton) Oxiran 3,3-Diethyl-2-ethenyl-2-methyl- E19d, 880 (Cl —C — C-OLi - Oxiran)... 

Ethoxy-ethenyl)- 1-hydroxy-E15/1, 230 (2-Br—enol-ether + R —Li/Keton)... 

Cyclopentadien 5-Amino-pentame-thyl- E16d, 1107 (M - NH2) Cyclopenten 1-Piperidino- E15/1, 609 (Keton + Amin) Cyclopropan 1-Ethenyl-l-piperidino-E17b, 1586 (OSCRj CH = CH2)... 

Propadien 3-Cyclohexyl-l-ethoxy-E15/3, 2973 (In 1,2-Dien) Spiro 3.5]nonan 9,9-Dimethyl-7-oxo-E19d. 871 (Br - Li/+ Keton Ringerweiterung) Tetrahydropyran 6-Ethenyl-2-(2-methyl-l-propenyl)- E2le, 4791 (7-OH-1,2-din + AgN03) Tricyclo(4.3.1.12 S undecan 1-... 

Tetralin 2-Methyl-2-(2-nitro-ethenyl)-l-oxo- E15/1, 1176f. (Keton + R2N-CH = CR-N02)... 

Cyclohepten 5-Oxo-4-phenyl- E17c, 2595 (2-Acyl-l-ethenyl-cyclopro-pan/Li —NR2 + R3Si —Cl) Cyclohexen 4-Benzoyl- E13/2, 1156 (Alkohol - Keton)... 

Cyclobntan 2-Ethenyl-1 -(4-methyl-benzolsulfonylhydrazono)- E14b, 1031 (Keton + Sulfonyl-hydra-zin)... 

Methyl-3-[N-(l-phenyl-ethyl)-hydroxyamino]- -methylester E16a, 127 (R-NH-OH + En) Pyridin 3-(Dimethoxy-methyl)-4-(fnmy-3-hydroxy-cyclopentyl)-E7b/2, 483 C-[CH(OR)2]-1,2,4-triazin + 3-OH —1-(CO — CH3) — cyclopentan Pyridin-l-oxid 4-Ethoxy-2-(l-hydroxy-cyclohexyl)- E19d. 605 (H - Li/ -(- Keton) Pymolo l,2-a azepin 6-Ethenyl-5-methoxycarbonyl-3-oxo-(5R, 6S, 9aR )-octa-hy dro-E21b, 1974 l-[CH(OH) —... 

Bicyclo[2.2.1]hepten 5-(2,2-Dieth-oxy-ethenyl)- E15/2, 1680 [ -CH(OR)2 + R-CHO] Bntan l,3-Dioxo-l-(2,6,6-trimethyl-1 -cyclohexenyl)-(9-Hydroxy- -damascon) El9b, 1261 (Hydroxy — carben - Keton) Cyclohexan... 

Significant progress has been made towards the understanding of proton delivery 152,165 Diastereomeric silyl ethenyl ethers 145 and 148 decompose on addition of TBAF and AcOH into the corresponding enols 146 and 149, which yield with AcOH two complementary bicyclic ketones (147 and 150, respectively), in different degrees of diastereomeric purity (equations 40 and 41). Two different proton transfer processes take place Bicyclic ketone 147 is formed by external delivery of a proton to 146 on its less hindered face (equation 40) the complementary ketone 150 is formed by protonation of 149 on its more hindered face (equation 41), invoking internal proton dehvery from the intermediate pyridinium acetate 151. For a more sterically demanding and weaker acid, such as phenol, the diastereoselectivity increased for 147 but reversed for 150. ... 

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