Cyclohexene, 3-methyl 4-vinyl

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). 

In a 200-ml three-necked flask fitted with a dropping funnel (drying tube) is placed a solution of 13.4 g (0.12 mole) of 1-octene in 35 ml of THF. The flask is flushed with nitrogen and 3.7 ml of a 0.5 M solution of diborane (0.012 mole of hydride) in THF is added to carry out the hydroboration. (See Chapter 4, Section I regarding preparation of diborane in THF.) After 1 hour, 1.8 ml (0.1 mole) of water is added, followed by 4.4 g (0.06 mole) of methyl vinyl ketone, and the mixture is stirred for 1 hour at room temperature. The solvent is removed, and the residue is dissolved in ether, dried, and distilled. 2-Dodecanone has bp 119710 mm, 24571 atm. (The product contains 15 % of 5-methyl-2-undecane.) The reaction sequence can be applied successfully to a variety of olefins including cyclopentene, cyclohexene, and norbornene. 

Morpholino-l-cyclohexene (Chapter 9, Section I) A Methyl vinyl ketone MCB, A... 

Methyl phenyl sulfide, see Thioanisole Methyl phenyl sulfoxide, 46, 78 from methylsulfinyl chloride and benzene with anhydrous alumi num chloride, 46, 80 Methyl vinyl ketone, reaction with 1-morpholino 1 cyclohexene, 45,... 

Morpholmo-l cyclohexene, reaction with methyl vinyl ketone, 46, 80... 

Such a rearrangement was detected only in the presence of sulfuric acid, and furthermore at 100°C. it was supplanted by a homolytic breakdown. The products found in the purely thermal decomposition—methyl vinyl ketone and methyl vinyl carbinol—are in fact consistent with the behavior of alkyl hydroperoxides and are analogous to the products produced from the cyclic allylic hydroperoxide from cyclohexene (2). 

Wiersum and Mijs found that in ice-cold ethereal solution 4 reacts instantaneously with maleic anhydride, A-phenylmaleimide, and methyl vinyl ketone to give 82, 83, and 84, respectively, in quantitative yield as endo-exo mixtures (endo exo = 3 1). Longer reaction times are needed with styrene and cyclohexene (2 hr, room temp.) compounds 85 and 86 are... 

Regiospecific cycloaddition of 65 a, b, and c to furan has also been observed. None of the oxazolinones give photoadducts with other olefins, including methyl vinyl ether, cyclohexene, cis-2-butene, trans-2-butene, and styrene. 

Fig (7) The transformation of cyclohexene-l,3-dione (50) to ketone (52) is described. This involves reduction, terahydropyranilation, methoxy-carbonylation and Michael addition, with methyl vinyl ketone. Treatment of (52) with p-TsOH in methanol, leads the formation of lactone (53) and hydroxy ester (54). The lactone (53) is regarded as an appropiate intermediate for natural o-methyl pisiferic acid (+)(2)and hydroxi ester (54) is intermediate for (-)(55). 

Diels-Adler 2,3-Dimethyl- butadiene Methyl vinyl ketone ((C4F4S03)2N)3La 4-Acetyl-1,2-dimethyl-cyclohexene 86... 

Since both oxidative splitting of the double bond and aldol condensation represent reliable and general reactions, their sequence serves as an efficient route for the transformation of readily available cyclohexene systems e.g. formed via the Diels-Alder reaction or Robinson annulation) into functionalized cyclopentene derivatives. This standard operational mode is extensively used in total syntheses. One of the numerous examples, the synthesis of helminthosporal 463, the sesquiterpenoid toxin of fungi, is shown in Scheme 2.150. In the initial phases of the synthesis, commercially available (—)-carvomenthone 464 was transformed into 465 via Michael reaction with methyl vinyl ketone to give 466 and subsequent intramolecular aldol condensation. 

Z)-2-Methoxy-l-(phenylthio)-l,3-butadienes react with methyl vinyl ketone and with 2-cyclohexen-1-one under catdysis by magnesium bromide or ethylaluminum dichloride. This provides exclusively the C 0 endo adducts in which the regiochemistry is completely controlled by the sulfur substituent despite the juxtaposed influence of the OMe group, e.g. (143) (144) (Scheme 36). ... 

This is a mild, simple and practical procedure for 1,4-addition of an aldehyde to methyl vinyl ketone, without converting the aldehyde into an enamine or a silyl enol ether. The products, substituted 5-ketoaldehydes, are important compounds, especially for the preparation of substituted 2-cyclohexen-1-one derivatives, which have been versatile starting materials for syntheses of natural products such as terpenoids. These 5-ketoaldehydes have been prepared previously by the 1,4-addition of modified aldehydes, i.e., morpholinoenamines of aldehydes,trimethylsilyl enol ethers of aldehydes in the presence of a Lewis acid, or diethylallylamine in the presence of a catalytic amount of a Ru complex, to methyl vinyl ketones. 

Nonphotochemical cycloadditions of hexafluorothioacetone to alkenes (vinyl ethers, vinyl sulfides, " cyclohexene, and dimethyl maleate " ) have been observed, as illustrated for methyl vinyl ether. The formal addition of thiocarbonyl fluoride to tetrafluorethylene to give hexafluorothietane occurs on thermolysis at 600-700° (lO " mm) of a copolymer of the two components. " QO-Dimethyldithiooxalate undergoes a thermal cycloaddition to quadricyclane to give thietane 51a. ... 

In our method, the N,N-diethyl butadienyl carbamates (1) reacts both regio and stereospecifically to methyl vinyl ketone to give the cyclohexene (II) in 89% yield, which in turn adds the Grignard s reagent (III), again regio and ste-... 

Another type of compound having the furo-furanone skeleton, in which a C—C bond was formed at C-2 of 3, has been achieved by using 3 as a Michael carbanion donor to various a, 3-unsaturated carbonyl compounds. Thus, it gives 94a when combined with methyl vinyl ketone, which can then be converted to the cyclic acetal upon reaction with methyl alcohol in the presence of an acid (83T2137). The reaction was extended to acrolein, a-methyl acrolein, and crotonaldehyde to give 94c. Its application with 2-cyclohexen-l-one required an unexpected acid catalysis to give 94b. On the other hand, extending the reaction to a cyclic enedione,... 

Product 58 was obtained in 52% yield and 100% selectivity. Differences in reactivity were observed, related to the nature of the reagents thus diethyl malonate reacted with methyl vinyl ketone, furnishing the Michael adduct in 34% yield after 30 min, whereas the adduct with 2-cyclohexen-l-one was obtained in 15% yield after 60 h. 

Spiroannelation. This phosphonate reacts with ketones to form enamines (2). These products react with methyl vinyl ketone (followed by hydrolysis) to 8keto aldehydes (3), which are converted spontaneously into 4,4-di-substituted 2-cyclohexene-i-ones (4). 

Buten-2-ol, 4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-, acetate. See a-lonyl acetate Butenone 1-Buten-3-one 2-Butenone. See Methyl vinyl ketone... 

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