2-Cyclohexene-l-one

Progress has been made toward enantioselective and highly regioselective Michael type alkylations of 2-cyclohexen-l -one using alkylcuprates with chiral auxiliary ligands, e. g., anions of either enantiomer of N-[2-(dimethylamino)ethyl]ephedrine (E. J. Corey, 1986), of (S)-2-(methoxymethyl)pyrrolidine (from L-proline R. K. EHeter, 1987) or of chiramt (= (R,R)-N-(l-phenylethyl)-7-[(l-phenylethyl)iinino]-l,3,5-cycloheptatrien-l-amine, a chiral aminotro-ponimine G. M. Villacorta, 1988). Enantioselectivities of up to 95% have been reported. 

Isophorone. Isophorone (3,5,5-trimethyl-2-cyclohexen-l-one) is a cycHc a,P-unsaturated ketone derived from the trimeri2ation of acetone. It has a light yellow color and a disagreeable camphoraceous odor. It has the tendency to discolor and form residues on prolonged storage. Isophorone is completely miscible with organic solvents, and other physical properties are Hsted ia Table 1. 

Chlorination of 2,6-dichlorophenol by chlorine at 70°C gives a yield of only 85%. Fifteen percent of the mixture is made up of 2,4,5,6,6-pentachloro-2-cyclohexen-l-one, the formation of which can be explained by the foUowiag mechanism ... 

TRIMETHYL-2-(2-OXOPROPYL)-2-CYCLOHEXEN-l-ONE [2-Cyclohexen-l-one, 3,5,5-trimethyl-2- (2-oxopropyl)-]... 

Reaction of 3,5,5-trimethyl-2-cyclohexen-l-one with NaNH2 (3 equiv) in THF generates its enolate. When bromobenzene is then added to this solution and stirred for 4h, the product A is isolated in 30% yield. Formulate a mechanism for this transformation. 

Chemical Designations - Synonyms 3,5,5-Trimethyl-2-cyclohexene-l-one Chemical Formula C0CH=C(CH3)CH2C(CH3)2CH2... 

Reaction of the morpholine or piperidine enamine of cyclopentanone, however, gives an unstable adduct which rearranges under the reaction conditions and an aqueous work-up to give the ring expanded ketone 2-chloro-2-cyclohexen-l-one (203) (138,139). 

The conjugate addition of medium-order cuprate reagents Li2Cu3Bu5 to 2-cyclohexen-l-one in the presence of 2 equivalents of (4S,5/ )-2-dimethylamino-3-isopropyl-4-methyl-5-... 

A portion of the product was heated to reflux with methanolic sodium methoxide to convert it into the thermodynamic mixture of trans- (ca. 65%) and cis- (ca. 35%) isomers. Small amounts of the isomers were collected by preparative gas chromatography using an 8 mm. by 1.7 m. column containing 15% Carbowax 20M on Chromosorb W, and each isomer exhibited the expected spectral and analytical properties. The same thermodynamic mixture of isomers was prepared independently by lithium-ammonia reduction5 of 2-allyl-3-methyl-cyclohex-2-enone [2-Cyclohexen-l-one, 3-methyl-2-(2-propcnyl)-],6 followed by equilibration with methanolic sodium methoxide. 

Cyclohexen-l-ol, 2-methyl-5-(l-methyl-ethenyl) [994 8 9], 106 acetate (1205-42-1], 106 2-Cyclohexen-l-one, 3- 3-butenyl)-(22627-45-81,56... 

Cyclohexanones, 2-alkyl-5 methyl-, 56 Cyclohexene, 34 Cyclohexene, 1,6-dibromo-, 34 CYCLOHEXENE, 3-METHYL-, 101 Cyclohexene, 1-phenyl- [Benzene, (1-eyclohexen-l-yl)-], 106 2-Cyclohexen-l-ol, 2-bromo-, 34 2-Cyclohexen-l-ol, 3-methyl-, 101 2-Cyclohexen-l-one, 2-allyl-3-methyl-[2-Cyclohexen-l-one, 3-methyl-2-(2-piopenyl)-], 55... 

Cyclohexen-l-one, 3-methyl-, 53, 101 Cyclohexyl bromide [Cyclohexane, bromo ], 82... 

Cyclohexen-l-one is easily prepared by a two-step procedure from cyclohexane-1,3-dione.3 It is available from Fluka AG CH-9470 Buchs. 

Epoxyeyclohexanone has been prepared in 30% yield4 by epoxi-dation of 2-cyclohexen-l-one with alkaline hydrogen peroxide, using a procedure described for isophorone oxide (4,4,6-trimethyl-7-oxabicyclo[4.1.0]heptan-2-one).5 A better yield (66%) was obtained using f r/-butyl hydroperoxide (1,1-dimethylethylhydroperoxide) and Triton B in benzene solution.6 The procedure described here is simple and rapid. 

Cyclohexane, methyl, 55, 112 CYCLOHEXANECARBOXYLIC ACID, 1 cyano-2-methyl-, ethyl ester, 55, 57 CYCLOHEXANONE, 2,3-epoxy- [7-Oxa-bityUo[4 1 0]heptan-2-one], 55, 52 2-Cyclohexen-l-one, 55, 52 5-Cyclohexene-l,4-dione, 2,3-dichloro-2,5-di-fm-butyl- [5-Cyclohexene-l,4-dione, 2,3-dichloro-2,5-bis( 1,1-di-methylethyl)-], 55, 32 5-Cyclohexene-l, 4-dione, 2,3,5-tnchloro-... 

Cyclohexane, methyl-, 55, 112 CYCLOHEXANFCARBOXYLIC ACID, 1-cyano-2-methyl-, ethyl ester, 55, 57 2-Cyclohexen-l-one, 55, 52 5-Cyclohexene-1,4-dione, 2,3-dichloro-2,5-... 

When strong electron-withdrawing substituents were introduced at the a-or )S-carbon of the vinyl group, the styrenes acted as dienophiles. Thus cycloaddition of a-trifluoromethyl styrene (58) with Danishefsky s diene 59 afforded regioselectively a 1 1 mixture of cycloadducts which were then converted (Equation 2.20) into 4-phenyl-4-trifluoromethyl-2-cyclohexen-l-one [54]. 

Diels-Alder reaction of 2-cyclohexen-l-one (37) with diene 38 mainly afforded the exo adduct 39, the key intermediate in the synthesis of the bottom half of chlorothricolide [14] (Equation 5.4). 

Cycloalkenones and/or their derivatives can also behave as dienic partners in the Diels-Alder cycloaddition. It is well documented [41] that cyclic acetals, for example, can interconvert with ring-opened enol ether forms, in a reversible manner the latter compounds can then be trapped by various dienophiles. Thus dienes 119 and 120 reacted with [60]-fullerene (Ceo) at high pressure, affording highly thermally stable products [42] (Scheme 5.16). Ketones 123 and 124 could be directly obtained by cycloaddition of enol forms 121 and 122 of 2-cyclopen-ten-and 2-cyclohexen-l-one, respectively. 

C H, 0 108-94-1) see Calusterone Clinofibrate Cyclobarbital Cyclobutyrol Cyclovalone Ethinamate Gabapentin Guanadrel Hexobarbital Levorphanol Orlistat Ramatroban Tacrine Tenylidone Venlafaxine 2-cyclohexen-l-one (CjHjO 930-68-7) see Carprofen... 

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... 

The enolized form of 2-acetyl-2-cyclohexen-l-one has been synthesized in low yield by dehydrochlorination of 2-acetyl-2-chlorocyclohexanone in collidine at 180° and by elimination of acetamide from 3-acetamido-2-acetylcyclohexanone at 120-140°. The preparation of other a,/3-unsaturated /3-dicarbonyl compounds has been attempted with varying degrees of success. The... 

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