Cyclohex-l-ene 1-

A solution of 2-methyl-l-(trimethylsilyloxy)cyclohex-l-ene (10 mmol) in dichloromethane (8 ml) was added dropwise over 15 min with stirring to acetyl chloride (10 mmol) and TiCl4 (10 mmol) in dichloromethane (15 ml) at -78 °C. After 1 h at -78 °C, the reaction mixture was allowed to warm to ambient temperature over 2h. It was then diluted with ether (20ml), and poured into saturated sodium hydrogen carbonate solution (50 ml). Normal work-up, followed by chromatography on silica gel, gave the /1-diketone (9.1 mmol, 91%). 

An example of the Diels Alder reaction of furans is the cycloaddition of 31 with 4,4-diethoxybut-2-ynal (32) which acts as an acetylenedicarbaldehyde synthon to afford 7-oxabicyclo [2.2.1]heptene derivatives [29] which were then converted into substituted cyclohex-l-ene-l,6-dicarbaldehydes by a four-step procedure (Scheme 2.14). 

Perrotta JA, CS Harwood (1994) Anaerobic metabolism of cyclohex-l-ene-l-carboxylate, a proposed intermediate of benzoate degradation by Rhodopseudomonas palustris. Appl Environ Microbiol 60 1775-1782. 

Cyclohexadiene-1.4-dione, see p-Quinone 1,4-Cyclohexadiene dioxide, see p-Quinone Cyclohexatriene, see Benzene Cyclohex-l-ene, see Cyclohexene... 

Mancini, I. Guella, G. Pietra, F. (2000) Highly diastereoselective, biogenetically-pattemed synthesis of (+)(15, 67J)-volvatellin (= (+)-(47 ,55)-5-hydroxy-4-(5-methyl-l-methylenehex-4-en-2-ynyl)cyclohex-l-ene-l-carboxaldehyde. Helv. Chim. Acta, 83, 694-701. 

Similarly, (ft)-( + )-6,6-dimcthylbicyclo[3.1, l]heptan-2-one [(R)-( + )-nopinone, 59] undergoes boron trifluoride promoted cyclobutane cleavage to give in 68% yield (4/ )-l-acetoxy-4-(2-acetoxy-2-propyl)cyclohex-l-ene (60).168,169... 

Antimony(V) fluoride reacts with almost all common solvents. For this reason the fluo-rination of hexachlorobenzene with antimony(V) fluoride is carried out using antimony(V) chloride as the solvent with heating at reflux for 1 hour. The mixture of products (49 % conversion) contains 33 compounds, mainly l,2-dichloro-3,3,4,4,5,5,6,6-octafluorocyclohcx-1-cne (56 %), 1,2,4,5-tetrachloro-3,3,6,6-tetrafluorocyclohexa-1,4-diene (16%), 1,2,4,5-tet rachloro-3,3,4,5.6,6-hexafluorocyclohex-1-ene (7%), and l,2,4-trichloro-3.3.4,5,5,6,6-hcptafluoro-cyclohex-l-ene (5%).94... 

Dehydrobromination of m-and tra/w-l-bromo-2-(bromodifluoromethyl)cyclohexane(44) with potassium hydroxide gives products 45, 46, and the hydrolysis product cyclohex-l-ene-l-car-bonyl fluoride (47).83... 

Pretazetiine. Ishibashi s formal synthesis [96] of the alkaloid 369 [97] (Scheme 54) in the racemic form commenced with 4-methoxy-l-(3 ,4 -methylenedioxyphenyl)-cyclohex-l-ene (370), which was converted into a mixture of P-bromohydrin 371 and the a-isomer 372. 

To a solution of 7-methanesulfonyloxy-2,2-dimethyl-3a,6,7,7a-tetrahydro-benzo[l,3]dioxole-carboxylic acid methyl ester (35.85 g, 117 mmol) in methanol (500 ml) was added p-toluenesulfonic acid (1.11 g, 5.85 mmol, 5 mol %) and the solution was refluxed for 1.5 h and was evaporated. The residue was redissolved in methanol (500 ml) and was refluxed an additional 4 h. The solvent was evaporated and the crude oil was triturated with diethyl ether (250 ml). After completing the crystallization overnight at 0°C, the solid was filtered and was washed with cold diethyl ether, and dried to afford 3,4-dihydroxy-5-methanesulfonyloxy-cyclohex-l-enecarboxylic acid methyl ester (24.76 g) as a white solid. Evaporation of the filtrate and crystallization of the residue from methanol/diethyl ether gave an additional 1.55 g. Obtained 26.3 g (85%) of the 3,4-dihydroxy-5-methanesulfonyloxy-cyclohex-l-ene-l-carboxylic acid methyl ester. 

A suspension of 3,4-dihydroxy-5-methanesulfonyloxy-cyclohex-l-ene-l-carboxylic acid methyl ester (20.78 g, 78 mmol) in tetrahydrofuran (400 ml) at 0°C was treated with l,8-diazabicyclo[5.4.0]undec-7-ene (11.7 ml, 78 mmol) and was stirred at room temperature for 9 h at which time the reaction was complete. The reaction was evaporated and the crude residue was dissolved in CH2CI2 (200 ml) and was washed with saturated NaCI (300 ml). The aqueous phase was extracted with CH2CI2 (2 times 200 ml). The combined organic extracts were dried (MgS04), filtered, and evaporated. The crude product was purified on silica gel (ethyl acetate) to afford 5-hydroxy-7-oxa-bicyclo[4.1.0]hept-3-ene-3-carboxylic acid methyl ester (12 g, 90%) as a white solid. 

C for 21 h. The reaction mixture was cooled to room temperature, diluted with ethyl acetate (about 100 ml) and was filtered. The filtrate was evaporated and the residue was partitioned between diethyl ether (100 ml) and saturated NaCI (100 ml). The organic phase was washed again with saturated NaCI (100 ml), dried (MgS04), filtered, and was evaporated. Additional crude product was obtained from the aqueous washings by extraction with ethyl acetate and treated in the same manner as described above. The crude product was purified on silica gel (5% MeOH/CH2CI2) to afford 4-amino-5-azido-3-methoxymethoxy-cyclohex-l-ene-l-carboxylic acid methyl ester (2.95 g) as an oil which contained a small amount of triphenylphosphine oxide impurity from the previous step. 

To a solution of 4-acethylamino-5-azido-3-(l-ethyl-propoxy)-cyclohex-l-ene-1-carboxylic acid methyl ester (268 mg, 0.83 mmol) in THF (7.0 ml) was added aqueous KOH (1.60 ml of a 1.039 N solution) at room temperature. After stirring for 19 h at room temperature the reaction was acidified to pH 4.0 with Amberlite IR-120 (H+) acidic resin. The resin was filtered and washed with water and ethanol. Concentration in vacuo gave the crude 4-... 

Triphenylphosphine (342 mg, 1.30 mmol) was added in one portion to a solution of 4-acethylamino-5-azido-3-(l-ethyl-propoxy)-cyclohex-l-ene-l-carboxyllic acid ethyl ester (272 g, 0.80 mmol) in THF (17 ml) and water (1.6 ml). The reaction was then heated at 50°C for 10 h, cooled and concentrated in vacuo to give a pale white solid. Purification of the crude solid by flash chromatography on silica gel (50% methanol in ethyl acetate) gave 242 mg (96%) of the 4-acethylamino-5-amino -3-(l-ethyl-propoxy)-cyclohex-l-ene-l-carboxyllic acid ethyl ester as a pale solid. 

The racemic mixture are separated into their individual, substantially optically pure isomers through well-known techniques such as, for example, the separation of diastereomeric salts formed with optically active adjuncts, e.g. acids or bases followed by conversion back to the optically active substances. So the 4-acethylamino-5-amino-3-(l-ethyl-propoxy)-cyclohex-l-ene-l-carboxyllic acid ethyl ester,(3a,4p,5a) was obtained. 

The 4-acethylamino-5-amino-3-(l-ethyl-propoxy)-cyclohex-l-ene-l-carboxyllic acid ethyl ester, (3a,4p,5a) is dissolved in H3P04 to give the corresponding water soluble salt form. 

The aldol condensations were carried out with the enolates derived from 3-oxocyclopent-1-ene or 3-oxo-cyclohex-l-ene and benzaldehyde or butyraldehyde1 (see p. 186, 443). 

First, following the results of the 1,6-dioxa-spiro[2.5]octane rearrangement (5,19), continuous gas phase conditions were applied in a fixed bed reactor and secondly under liquid phase conditions in a slurry reactor. The catalytic experiments carried out showed that two main reactions took place rearrangement of 18 to the aldehyde 19 and a oxidative decarbonylation reaction to the olefine 1,3,3,4-tetramethyl-cyclohex-l-ene 20, which is assumed to be caused by a formaldehyde elimination reaction. Also observed was a deoxygenation reaction to the alkane 1,1,2,5-tetra-methylcyclohexane 21 (Eq. 15.2.7), explained by elimination of CO. There are several other side-products such as 2,2,3,6-tetramethylcyclohex-l-enyl-methanol, ringcontracting compounds and double bond isomers of dimethyl-isopropylene-cyclopentene. 

To a mixture of l,2-bis(trimethylsilyloxy)cyclohex-l-ene (67.6g) and potassium tert-butoxide (52.1 g) dissolved in 600ml of pentane, 25.1ml chloroform was added over 30 minutes at ambient temperature. After an additional 30 minutes, 10 ml 10% HCl and 30 ml water were added and the mixture reacted one hour. The mixture was poured into 200 ml saturated NaHC03 solution, the aqueous layer washed twice with EtOAc, and the pH adjusted to 3 using 5% HCl. The product was extracted with chloroform, the solution washed, dried, and 22 g of product isolated. H-NMR and MS data supplied. 

Fig. 6 Possible ring structures of poly( 1,6-heptadiynes) prepared via cyclopolymerization. Poly(cyclopent-l-enylene-l-vinylene)s (A) poly(cyclohex-l-ene-3-methylidene)s (B) and mixed structures (C)...

SYNS CYCLOHEX-l-ENE-l-METHANOL, 4-(l -METH-YLETHENYL)- DIHYDROCUMINYL ALCOHOL 4-ISOPROPENYL-CYCLOHEX-l-ENE-l-METHANOL p-MENTHA-l,8-DIEN-7-OL PERILLOL PERJLLYL ALCOHOL... 

Reactions with Sulfur Nucleophiles. The use of sulfur nucleophiles in palladium-catalyzed allylic substitution reactions is less well documented than that of carbon, nitrogen and oxygen nucleophiles. The asymmetric synthesis of allylic sulfones utilizing a catalytic phase transfer system has been used to produce (35)-(phenylsulfonyl)cyclohex-l-ene on a 45 g scale (eq 10). In many cases, it has been reported that allylic carbonates are more reactive than allylic acetates in asymmetric allylic substitution... 

More readily carbamoylation of 1-morpholinocyclohexene with 1-naphthyl isocyanate gave a mixture of isomeric 2-morpholino-A -(l-naphthyl)cyclohex-l(or2)-ene-l-carboxamide in 85% yield. Successive treatment with 7V-chlorosuccinimide (NCS) in acetonitrile gave 3-chloro-2-morpholino-iV-(l-naphthyl)cyclohex-l-ene-l-carboxamide (21) in 74% yield. 

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