Cyclohexene 4-ethyl

Pyrrole ring. Ene-l,2-di(oxysilanes) can be used in place of acyloins for the synthesis of various heterocyclics. - E l,2-Bis(trimethylsiloxy)cyclohexene, ethyl /9-aminocrotonate, and glacial acetic acid heated 1 hr. at 100° ethyl 4,5,6,7-tetrahydro-2-methylindole-3-carboxylate. Y 96%. F. e. and heterocyclics s. K. Riihlmann et al., J. pr. 311, 844 (1969). 

C2H4+-, CO+-, N2+ , HCNH+ [M-28]+- (C2H4) nonspecific abundant cyclohexenes, ethyl esters, propyl ketones, propyl-substituted aromatics... 

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. 

The reaction of cyclohexene with the diazopyruvate 25 gives unexpectedly ethyl 3-cyclohexenyl malonate (26), involving Wolff rearrangement. No cyclo-propanation takes place[28]. 1,3-Dipolar cycloaddition takes place by the reaction of acrylonitrile with diazoacetate to afford the oxazole derivative 27[29]. Bis(trimethylstannyl)diazomethane (28) undergoes Pd(0)-catalyzed rearrangement to give the A -stannylcarbodiimide 29 under mild conditions[30]. 

Cyclohexenone has been prepared by dehydrohalogenation of 2-bromocyclohexanone, by the hydrolysis and oxidation of 3-chlorocyclohexene, by the dehydration of a-hydroxycyclohexa- ione, by the oxidation of cyclohexene with chromic acid or hydrogen peroxide in the presence of a vanadium catalyst, by I lie addition of acroleiti to ethyl acetoacctate followed by cycliza-lion, hydroly.sis, and decar])oxylation, by the reduction of N,N-dimelliyliiniline with sodium and ethanol itt liquid ammonia... 

At higher temperatures the mixture of 10 and methyl vinyl ketone yields the 1,4-carbocyclic compound as described previously. Methyl isopropenyl ketone (5), ethyl acetylacrylate (d), 2-cyclohexenone (21), and 1-acetyl-1-cyclohexene (22) also undergo this type of cyclization reaction with enamines at higher temperatures. This cycloalkylation reaction occurs with enamines made of strongly basic amines such as pyrrolidine, but the less reactive morpholine enamine combines with methyl vinyl ketone to give only a simple alkylated product (7). Chlorovinyl ketones yield pyrans when allowed to react with the enamines of either alicyclic ketones or aldehydes (23). 

A dry 5(X)-mI flask equipped with a thermometer, pressure-equalizing dropping funnel, and magnetic stirrer is flushed with nitrogen and then maintained under a static pressure of the gas. The flask is charged with 50 ml of tetrahydrofuran and 13.3 ml (0.15 mole) of cyclopentene, and then is cooled in an ice bath. Conversion to tricyclo-pentylborane is achieved by dropwise addition of 25 ml of a 1 M solution of diborane (0.15 mole of hydride see Chapter 4, Section 1 for preparation) in tetrahydrofuran. The solution is stirred for 1 hour at 25° and again cooled in an ice bath, and 25 ml of dry t-butyl alcohol is added, followed by 5.5 ml (0.05 mole) of ethyl bromoacetate. Potassium t-butoxide in /-butyl alcohol (50 ml of a 1 M solution) is added over a period of 10 minutes. There is an immediate precipitation of potassium bromide. The reaction mixture is filtered from the potassium bromide and distilled. Ethyl cyclopentylacetate, bp 101730 mm, 1.4398, is obtained in about 75% yield. Similarly, the reaction can be applied to a variety of olefins including 2-butene, cyclohexene, and norbornene. 

Chemical Name 2-(dimethylamino)-1-phenyl-3-cyclohexene-1-carboxylic acid ethyl ester hydrochloride... 

Isomer (I) 4-phenyl-3-cis-dimethylamino-4-cis-carbethoxy-A -cyclohexene hydrochloride, [ethyl-cis-3-(dimethylamino)-4-phenyl-1-cyclohexene-4-carboxylate hydrochloride], MP 84°C (the free base boils at 97.5" to 98°C at 0.01 mm pressure), 64.4% yield. 

Cyclohexadiene has been prepared by dehydration of cyclohexen-3-ol,3 by pyrolysis at 540° of the diacetate of cyclohexane-1,2-diol,4 by dehydrobromination with quinoline of 3-hromocyclohexene,6 by treating the ethyl ether of cyclohexen-3-ol with potassium bisulfatc,6 7 by heating cyclohexene oxide with phthalic anhydride,8 by treating cyclohexane-1,2-diol with concentrated sulfuric acid,9 by treatment of 1,2-dibromocyclo-hexane with tributylamine,10 with sodium hydroxide in ethylene glycol,10 and with quinoline,6 and by treatment of 3,6-dibromo-cyclohexene with sodium.6... 

Similar stereochemical results were obtained from the addition of the potassium and lithium ions of ethyl acetate, /V,V-dimethylacetamide, acetonitrile, acetophenone and pinacolone to 3-(/erf-butyldimethylsilyloxy)-T-phenylsulfonyl-1-cyclohexene followed by protonation or methylation of the resulting sulfonyl carbanion intermediates7. 

Hagemann s ester [2-Cyclohexene-1-carboxy lie acid, 2-methyl-4-oxo-, ethyl ester], 55... 

Cyclohexene, purification of, 41, 74 reaction with zinc-copper couple and methylene iodide, 41, 73 2-CyclohEXENONE, 40,14 Cydohexylamine, reaction with ethyl formate, 41, 14... 

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-... 

CN (3/ ,4/ ,5S)-4-(Acetylamino)-5-amino-3-(l-ethylpropoxy)-l-cyclohexene-1-carboxylic acid ethyl ester phosphate... 

RN 51931-66-9 MF C,7H23N02 MW 273.38 EINECS 243-774-7 CN fro/i.v-2-(dimethylamino)-i-phenyl-3-cyclohexene-l-carboxylic acid ethyl ester... 

Diethylaminobutadiene reacts with ethyl acrylate and exclusively gives 3,4-disubstituted cyclohexene product (Scheme 13a) [13, 14], The reaction of... 

A. trans-l,2-Cyclohexanediol. In a 100-ml., round-bottomed flask equipped with a reflux condenser protected with a drying tube are placed a magnetic stirring bar, 17.56 g. (0.0667 mole) of thallium (I) acetate (Note 1), and 40 ml. of dried acetic acid (Note 2). The mixture is stirred and heated at reflux for 1 hour. To the cooled mixture are added 2.84 g. (3.5 ml., 0.0346 mole) of cyclohexene (Note 3) and 8.46 g. (0.0333 mole) of iodine (Note 4). The resulting suspension is stirred and heated at reflux for 9 hours (Note 5), and then cooled to room temperature. The yellow precipitate of thallium(I) iodide is filtered and washed thoroughly with ethyl ether. The filtrates are comhined, the solvents are removed under reduced pressure with a rotary evaporator (Note 6), and the residual liquid is dissolved in dry ethyl ether. The turbid solution is dried with anhydrous potassium carbonate, and the solvent is again removed by rotary evaporation (Note 6), affording 5.4-6.3 g. of trans-1,2-cyclohexanediol diacetate as a mobile, brown liquid (Note 7). 

Ethylenedioxybutyl)-3-trichloro-acetamido-l-cyclohexene, 58, 9, 11 Ethylene glycol, 56, 44 Ethyl a-fluoro-l-naphthaleneacetate, 57, 73 Ethyl 2-fluoropropanoate, 57, 73 3-Ethylhexane, 58, 3, 4 3-ETHYL-l-HEXYNE, 58, 1, 2, 3, 4 Ethylidenecyclohexane, 59, 46 Ethyliodide, 59, 133 Ethyl 2-iodo-3-nitropropionate, 56,65 Ethyl isocyanide, 55, 98 Ethyl isocyanoacetate, 59,184 l-Ethyl-4-isopropylbenzene, 55,10 Ethyl levulinates, 5-substituted, 58, 81 ETHYL 2-METHYL1NDOLE-5CARBOXY-LATE, 56, 72... 

List B contains all compounds that form peroxides which become dangerous when they reach a critical concentration. The danger will often become apparent during distillation operations. For hydrocarbons, this is the case for deca- and tetrahydronaphthalene, cyclohexene, dicyclopentadiene, propyne and butadiene. S ondary alcohols such as 2-butanol also form part of this list. Finally, for ethers there are diethyl ethers, ethyl and vinyl ethers, tetrahydrofuran, 1,4-dioxan, ethylene glycol diethers and monoethers. 

It has been pointed out earlier that the anti/syn ratio of ethyl bicyclo[4.1,0]heptane-7-carboxylate, which arises from cyclohexene and ethyl diazoacetate, in the presence of Cul P(OMe)3 depends on the concentration of the catalyst57). Doyle reported, however, that for most combinations of alkene and catalyst (see Tables 2 and 7) neither concentration of the catalyst (G.5-4.0 mol- %) nor the rate of addition of the diazo ester nor the molar ratio of olefin to diazo ester affected the stereoselectivity. Thus, cyclopropanation of cyclohexene in the presence of copper catalysts seems to be a particular case, and it has been stated that the most appreciable variations of the anti/syn ratio occur in the presence of air, when allylic oxidation of cyclohexene becomes a competing process S9). As the yields for cyclohexene cyclopropanation with copper catalysts [except Cu(OTf)2] are low (Table 2), such variations in stereoselectivity are not very significant in terms of absolute yields anyway. 

Rh(II) pivalate is, however, still not efficient in producing more of the syn than of the anti isomer of ethyl bicyclo[4.1.0]heptane-7-carboxylate from cyclohexene and ethyl diazoacetate 87 98>. It needs a rhodium(III) porphyrin 47 to be successful in this case... 

For example, reaction of ethyl diazopyruvate with cyclohexene in the presence of rhodium 126) or copper113 126 catalysts furnishes, besides the 7-exo-substituted norcarane 108, a small amount of 110, which may arise either from allylic insertion or from the 7-mfo-substituted norcarane 109 by a thermal 1,5-homo-hydrogen shift. 

---