Methyl pent-2-enoate

Methyl pent-2-enoate-1 Ethyl pent-2-enoate-1 Ethyl pent-2-enoate-1 Ethyl pent-2-enoate-1... 

A most important application of butadiene carbonylations is BASF s development of a three-stage process for the synthesis of adipic acid from the butadiene-containing C4 cut [1] (eqs. (4) and (5)). Cobalt is the catalyst metal of choice for this process. The reaction takes place in two steps the first stage, which involves a lower temperature (100-140 °C), uses a fairly high concentration of HCo(CO)4 and pyridine as catalyst system to ensure rapid carbonylation of butadiene to give methyl pent-3-enoate in 90 % selectivity, thus avoiding typical side reactions such as dimerization and oligomerization. 

Hydroesterification of butadiene with CH3OH employing a Co catalyst can proceed in a stepwise fashion, initially to methyl 3-penteneoate and subsequently, under more rigorous conditions, to dimethyl adipate. Thus hydroesterification of an olefin stream containing 44% butadiene (remainder mostly butenes) with CH3OH, employing Co2(CO)g catalyst and an isoquinoline promoter, gave 98% methyl pent-3-enoate ° after... 

Methyl 4-methyl-pent-3-enoate Methyl 2-methyl-pent-3-enoate Methyl 2-keto-3-methylcyclo-pentylacetate Methyl 3,4-dime-thylpent-3-enoate... 

An extensive paper by Burgada et l. reports the reactions of cyclic phosphites (75 ab) and cyclic phosphoramidites (76 ab) with trans-1,2-dibenzoylethene, methyl fumarate, benzalacetone (PhCH=CH COMe), methyl-4-keto-pent-2-enoate (MeCO.CH=CH.COgMe) and benzalacetophenone (PhCH=CHCOPh)95. These reactions lead to... 

Branchadall and co-workers studied the effect of Lewis acid (AlCfO catalysis on the Diels-Alder reactions of methyl (Z)-(5)-4,5-(2,2-propylidenedioxy)pent-2-enoate (10) with cyclopentadiene, which usually exhibits a high level of syn-endo selectivity under the influence of the Lewis acid, at the B-LYP/6-31G level [16]. The most stable conformation of the complex IO-AICI3 revealed the significant difference with the structure of uncomplexed molecule, i.e., s-trans arrangement of the carbonyl group with respect to the carbon-carbon double bond (Fig. 1-3). 

The combination of diethylzinc and chloroiodomethane was employed in the synthesis of carbo-cyclic cyclopropyl nucleosides projected for biological evaluation. Attempts to cyclopropanate the intermediate a,j8-unsaturated ester, methyl (Z)-4,5-(isopropylidenedioxy)pent-2-enoate, gave a low yield (10%) of the desired cyclopropyl product. However, hydroxy-directed cyclo-propanation vide infra) of the reduced allyl alcohol 21 with diethylzinc/chloroiodomethane at 0°C afforded the cyclopropane derivative 22 in 54% yield. 

Similar reactions were observed when 1 -phenyldiazoethane was allowed to react with methyl ( )-2-cyano-3-(4-substituted phenyl)acrylates in dichloromethane at — 5 to 0 °C. The expected cyclopropanes, methyl 1 -cyano-3-methyl-3-phenyl-2-(4-substituted phenyl)cyclopropanecarb-oxylates 2, were formed in moderate to low yields. In addition, significant amounts of methyl 2-cyano-4-phenyl-4-(4-substituted phenyl)pent-2-enoates 3, formed by rearrangement from postulated dihydropyrazole intermediates, and methyl 4-cyano-3-methyl-3-phenyl-5-(l-phenyT l-(4-substituted phenyl)ethyl]-4,5-dihydro-3f/-pyrazole-4-carboxylates4, formed by 1-phenyldiazoethane attack on 3, were obtained. ... 

Formula 28b has been proposed for two by-products obtained after the reaction of methyl 3-acetyl-4-bromo-pent-2-enoate with a MeONa-MeOH mixture at 0°C (83BSB371). 

To a solution of methyl ( )-5-(2-iodophenyl)pent-2-enoate (159 mg, 0.5 mmol) in benzene (0.2 mL) and acetonitrile (0.2 mL) under a nitrogen atmosphere was added tetrakis(triphenylphosphine)palladium (58 mg, 0.05 mmol) and triethylamine (77 L, 0.55 mmol). The mixture was irradiated in the water bath of a Branson B-220H ultrasonic laboratory cleaner for 6 h. 

Another important reaction made possible by the presence of the aldehyde moiety is an olefmation reaction that extends the chain and adds a new carboxyl moiety. A Horner-Wadsworth-Emmons olefmationS of N-Cbz alinal (5.7) gave methyl 4-(N-Cbz amino)pent-2-enoate (5.8) as a mixture of cis trans isomers (>30 1). A number of other derivatives were prepared by starting with different amino acids. 

Thus, Simonneaux and co-workers have reported treatment of methyl allyl sulphide with 2-diazoethyl acetate at 25 in the presence of (SBF>4PRuCO as catalyst (homogeneous reaction, entry 1 in Table 4), which leads to ethyl-2-(methylthio)pent-4-enoate in 88 % yield with 8 % of dimers [56]. As presented in Scheme 21, the formation of ethyl-2-(methylthio)pent-4-enoate derives from the [2,3]-sigmatropic rearrangement of the sulphur ylide and that of the dimers (di-ethylfumarate and diethylmaleate) derives from 2-diazoethyl acetate dimerization. 

Ethyl (R.)-2-hydroxyl-2-methyl-4-(triisopropylsilyloxy)pent-4-enoate ... 

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