2-ACETYL-2-CYCLOHEXEN-1-ONE

Acetylacetonylbenzoic acid, 58, 55, 56 2-Acetyl-l,3-cyclohexadien-l-ol, 59, 62 Acetylcyclohexane, 55, 25 2-Acetylcyclohexanone, 59, 59 2-ACETYL-2-CYCLOHEXEN-1-ONE, 59,... 

The mild character of the reaction conditions is exemplified effectively here by the preparation of 2-acetyl-2-cyclohexen-l-one from 2-acetyIcyclohexanone. The crude product is initially isolated entirely in the less stable enedione form which is partially converted to the more stable enol form, 2-ace tyl-1,3-cyclohexadien-l-ol, during distillation at 45-55°. A series of a,(3-unsaturated j3-keto esters, -diketones, and a p-keto sulfoxide have also been prepared in the unenolized form by this... 

Also obtained by dehydrogenation of 6-acetyl-3-ethyl-4-methyl-2-cyclohexen-1-one,... 

METHOXYCARBONYL-1,1,6-TRIMETHYL-1,4,4a,5,6,7,8,8a-OCTAHYDRO-2,3-BENZOPYRONE, an intramolecular Diels-Alder reaction is responsible for the diastereoselectivity. The stereoselective 1,4-functionalization of 1,3-dienes is exemplified by a two-step process leading to cis- and trans-1-ACETOXY-4-(DICARBOMETHOXYMETHYL)-2-CYCLOHEXENE. The effectiveness of a silyl hydride in providing a means for erythro-directed reduction of a p-keto amide is applied in a route to ERYTHRO-1 -(3-HYDROXY-2-METHYL-3-PHENYL-PROPANOYLJPIPERIDINE. This is followed by an asymmetric synthesis based on a chiral bicyclic lactam leading to (R)-4-ETHYL-4-ALLYL-2-CYCLOHEXEN-1-ONE. The stereoselectivity with which acetoxy migration can operate to an adjacent radical center is reflected in the one-step reaction that gives rise to 1,3,4,6-TETRA-O-ACETYL-2-DEOXY-a-D-GLUCOPYRANOSE. 

A solution of 3-chloroperbenzoic acid (55%) in methylene chloride is cooled in an ice bath. (5R)-(-)-Carvone are added dropwise thereto so that the temperature does not rise above 20°C. The reaction mixture is stirred at room temperature for 3.5 h, whereby a precipitate of 3-chlorobenzoic acid forms. This suspension is stirred for 30 min and cooled with ice in order to complete the precipitation. The precipitate is filtered off and washed with hexane/methylene chloride (9 1). The filtrate is evaporated carefully. The thus-obtained oil (epoxide) is suspended in ice-water and treated with 3 N sulfuric acid while cooling in an ice bath so that the temperature does not rise above 20°C. The mixture is stirred at room temperature for 15 h. The pH is adjusted to 6.5 by adding 3 N sodium hydroxide solution. A small amount of 3-chlorobenzoic acid is filtered off. The aqueous phase is cooled to 0°C, whereupon sodium (meta)periodate are added in portions over 30 min so that the temperature does not rise above 20°C. After stirring at room temperature for 2 h sodium sulfite and sodium bicarbonate are added in succession. The suspension is filtered and the filtrate is extracted three times with methylene chloride each time. The combined organic phases are dried over sodium sulfate and evaporated. There is obtained (5R)-5-acetyl-2-methyl-2-cyclohexen-l-one (crystallized from hexane/ethyl acetate at 0°C). 

D. (1R ,6S , 7S )-4-(tert-Butyldimethylsiloxy)-6-(trimethylsilyl)bicyclo[5.4.0]-undec-4-en-2-one (4). A 100-mL, three-necked, round-bottomed flask, equipped with a magnetic stirring bar, a thermometer, a rubber septum, and a nitrogen inlet/outlet adapter, is placed under a nitrogen atmosphere and charged with 2.81 mL (2.17 g, 21.4 mmol) of diisopropylamine (Note 23) and 20 mL of dry THF. The solution is stirred and cooled with an ice-water bath while 13.7 mL (20.1 mmol) of a 1.47 M hexane solution of BuLi is added dropwise via a syringe over 5 min. After 10 min, the mixture is cooled to -80°C with a hexane-liquid nitrogen bath, and a solution of 2.58 mL (2.49 g, 20.1 mmol) of 1-acetyl-1-cyclohexene (Note 24) in 20 mL of dry THF is added dropwise via a stainless steel cannula over 15 min. The mixture is then stirred at the same temperature for an additional 30 min, and the solution is maintained at -80°C. 

Alkoxybicyclo[2.2.2]octan-2-ones. A soln. of 4-acetyl-1-methoxy-l-cyclohexene and p-toluenesulfonic acid in isobutanol refluxed 3 hrs., then slowly distilled to remove the solvent during 3-4 hrs. 4-isobutoxybicydo [2.2.2] octan-2-one. Y 76%. Also without transetherification and in other alcohols s. K. Morita and T. Kobayashi, J. Org. Chem. 31, 229 (1966) 4-aminobicydo[2.2.2]octan-2-ones s. J. Org. Chem. 31, 3106 cycloisomerization in benzene s. Y. Gaoni and R, Mechoulam, Am. Soc. 88, 5673 (1966). 

The preparation of 4-alkoxybicyclo [2.2.2] octan-2-ones from 4-acetyl-1-methoxy-l-cyclohexene by a novel cycloisomerization of 1,3-disubst. adamantanes by an exceptionally easy ring closure from suitable unsatd. cycloketones , and of cubane derivatives by an elegant three-step procedure have been reported. 

Acetic acid 2-hydroxy-3-oxo-3-phenylpropyl ester 3 - Acetoxy-1 -cyclohexene 17)3-Acetoxy-estr-5(10)-ene-3-one rrara-Cyclohexenyl diacetate 4-Acetyl- 1-Methylcyclohexene 3-(Azidopropenyl)benzene... 

Acetyl-l-methyl-l-cyclohexene [6090-09-1] M 138.2, 73-75 /7.5mm, 85-86 /13mm, 94-94.7 /20mm, 204.5-206 /747mm, d 1.0238, n p 1.469. Purified by fractionation under reduced pressure in vacuo, and when almost pure it can be fractionated at atmospheric pressure, preferably in an inert atm. Forms two semicarbazones one of which is more soluble in C H, and both can be recryst from EtOH, more soluble has m 149 (151 ), and the less soluble has m 172-175°(191°). 4-Nitrophenylhydrazone has m 166-167° and the 2,4-dinitrophenylhydrazone has m 114-115 . [/7CA 17 129, 140 1934 A 564 109 7949]. 7V-Acetyl-67V -methylglycinamide [7606-79-3] M 130.2. Recrystd from EtOH/Et2O mixture. 7V-Acetyl-67V -methyl-L-leucine amide [32483-15-1 ] M 186.3. Recrystd from EtOH/hexane mixture. 

Acetyl-1-cyclohexene (2). 1 (65.0 g 0.5 mol) in 90% HCOOH (400 mL) was refluxed for 45 min. The cooled mixture was poured into water (2000 mL) and extracted with petroleum ether. The organic layer was washed with 10% NaOH, the solvent evaporated and the residue was carefully fractionated. One obtains 32 g of 2 (49%), bp lire (49 mm). 

Higher alkenes can be acetylated in synthetically useful yield by treatment with AcCl together with various mild Lewis acids. One that deserves prominent mention is EthyUUununum Dkhlo-ride (CH2CI2, It), which is useful for acetylation of all classes of alkenes (monosubstituted, 1,2-disubstituted, and trisubstituted). For example, cyclohexene is converted into an 82/18 mixture of 3-acetylcyclohexene and 2-chlorocyclohexyl methyl ketone in 89% combined yield. 

---