Methyl cinnamate, reactions

As a typical example, the catalytic reaction of iodobenzene with methyl acrylate to afford methyl cinnamate (18) is explained by the sequences illustrated for the oxidative addition, insertion, and /3-elimination reactions. 

Further evidence showed this mechanism to be incorrect, especially the fact that it was methyl cinnamate and not (347) which was isolated from the reaction (73CPB2026). Also 1-phenylpyrazoles did not react with DMAD under the reaction conditions (74BSF2547). The origin of (346) remains obscure, but in no circumstances does it imply a Diels-Alder reaction of a pyrazole. For Ogura et al., it has its origin in an intermediate A -pyrazoline (73CPB2026). 

By heterogeneous reaction of methyl cinnamate, the C=C double bond is selectively hydrogenated [26] and methyl 3-phenylpropionate is formed the ester function is not affected. 

Table 3. Reaction between iodobenzene and methyl acrylate to methyl cinnamate in the presence of palladium catalysts...

In one study, the mechanisms of the reaction of methyl cinnamate and cyclopen-tadiene with BF3, A1C13, and catecholborane bromide as catalysts were compared.29 According to these computations (B3LYP/6-31G ), the uncatalyzed and BF3- and AlCl3-catalyzed reactions proceed by asynchronous concerted mechanisms, but a... 

Other ketones besides acetone can be used for in situ generation of dioxi-ranes by reaction with peroxysulfate or another suitable peroxide. More electrophilic ketones give more reactive dioxiranes. 3-Methyl-3-trifluoromethyldioxirane is a more reactive analog of DMDO.99 This reagent, which is generated in situ from 1,1,1-trifluoroacetone, can oxidize less reactive compounds such as methyl cinnamate. 

In 1989, Isayama and Mukaiyama reported a related Co-catalyzed coupling reaction that employs a,b-unsaturated nitriles, amides, and esters with PhSiLb as a hydrogen source [9]. Cobalt-bis(diketonato) complex, Co(II)(dpm)2 [dpm = bis(dipivaloylmethanato)] (5mol%), exhibited high catalytic activity at 20 °C in the coupling of excess acrylonitrile and ben-zaldehyde to provide b-hydroxy nitrile 4 in 93% yield (syn anti = 50 50) (Scheme 5). N,N-Dimethylacrylamide and methyl cinnamate both reacted... 

Formation of mixtures of the above type, which is common with internal olefins, do not occur with many functionalized alkenes. Thus, tertiary cinnamates and cinnamides undergo cycloadditions with benzonitrile oxides to give the 5-Ph and 4-Ph regioisomers in a 25-30 75-70 ratio. This result is in contrast to that obtained when methyl cinnamate was used as the dipolarophile (177). 1,3-Dipolar cycloaddition of nitrile oxides to ethyl o -hydroxycinnamate proceeds regiose-lectively to afford the corresponding ethyl fra s-3-aryl-4,5-dihydro-5-(2-hydro-xyphenyl)-4-isoxazolecarboxylates 36 (178). Reaction of 4-[( )-(2-ethoxycarbo-nylvinyl)] coumarin with acetonitrile oxide gives 37 (R = Me) and 38 in 73% and 3% yields, respectively, while reaction of the same dipolarophile with 4-methoxy-benzonitrile oxide affords only 37 (R = 4-MeOCr>H4) (85%) (179). 

Fig. 44.4 N MR-spectroscopic monitoring of the enantioselective hydrogenation of (Z)-N-acetylamino methyl cinnamate using [Rh((R,R)-DI PAM P) (COD)]BF4 as catalyst under stationary conditions (reaction conditions 0.01 mmol Rh-complex,...

The reaction between iodobenzene and methyl acrylate in scCC>2 using the Pd(OAc)2/fluorous-derivatized phosphine catalyst gave a superior yield of methyl cinnamate compared to the same reaction in a conventional organic solvent. The... 

Photochemical hydrogen abstraction reaction for the silylimine 161 give an o-quinodimethane intermediate 162 which could be trapped with dimethyl fumarate, dimethyl maleate, trans-methyl cinnamate, methyl acrylate, acrylonitrile (equation 94)... 

Scheme 61 Cyclic disulfides by reaction of with methyl cinnamate.

The variety of educts and products of the higher MCRs is illustrated here. Product 72 (Scheme 1.18) is formed from the five functional groups of lysine, benzaldehyde, and tert-butylisocyanide. The synthesis of 73 is achieved with hydrazine, furanaldehyde, malonic acid, and the isocyano methylester of acetic acid, compound 74 results from the reaction of benzylamine, 5-methyl-2-furanaldehyde, maleic acid mono-ethylester, and benzylisocyanide. ° Zhu et al. prepared a variety of related products, such as, 75, from (9-amino-methyl cinnamate, heptanal, and a-isocyano a-benzyl acetamides. 

Inverse isotope effects such as those found in Table IV are associated with a change in hybridization at the site of deuterium substitutions (60). Hence, it is clear from these data that the transition state is symmetrical with respect to hydridization changes at both olefinic carbons when the reaction is carried out in aqueous solutions. However the last four entries in Table IV indicate that for the oxidation of methyl cinnamate in methylene chloride solutions only the iS-carbon has undergone a hybridization change (from sp ... 

Much more conveniently, even a,)S-unsaturated esters can he transformed into a,)S-unsaturated alcohols by very careful treatment with lithium aluminum hydride [1073], sodium bis(2-methoxyethoxy)aluminum hydride [544] or diiso-butylalane [1151] (Procedure 18, p. 208). An excess of the reducing agent must be avoided. Therefore the inverse technique (addition of the hydride to the ester) is used and the reaction is usually carried out at low temperature. In hydrocarbons as solvents the reduction does not proceed further even at elevated temperatures. Methyl cinnamate was converted to cinnamyl alcohol in 73% yield when an equimolar amount of the ester was added to a suspension of lithium aluminum hydride in benzene and the mixture was heated at 59-60° for 14.5 hours [1073]. Ethyl cinnamate gave 75.5% yield of cinnamyl alcohol on inverse treatment with 1.1 mol of sodium bis(2-methoxy-ethoxy)aluminum hydride at 15-20° for 45 minutes [544]. 

Reduction of 4-methylcoumarin in aqueous buffers employed for the asymmetric reduction resembles the reactions of methyl cinnamate (p. 67) The process leads... 

On the other hand, reactions of nitrile oxides with 1,2-disubstituted olefins are slower and regioselectivity usually was not so high. For example, benzonitrile oxides, obtained from the corresponding chlorooximes 167, undergo 1,3-dipolar cycloaddition reaction with methyl cinnamate to produce the 5-phenyl 168 and 4-phenyl 169 regioisomers in approximately an 80 20 ratio °. However, use of A,iV-diethylcinnamamide as the dipolarophile... 

The 1,4-addition reaction of unsaturated carbonyl compounds with Ph3Bi smoothly proceeded in the presence of rhodium catalysts (Scheme 54) [67,68]. Interestingly, the reaction can be conducted in a H20/THF mixture under air. Methyl cinnamate, having an OH group on the aromatic ring, was efficiently phenylated without the protection of the OH group. 

The meso-ionic l,3-dithiol-4-ones (134) participate - in 1,3-dipolar cycloaddition reactions giving adducts of the general type 136. They show a remarkable degree of reactivity toward simple alkenes including tetramethylethylene, cyclopentene, norbomene, and norbor-nadiene as well as toward the more reactive 1,3-dipolarophilic olefins dimethyl maleate, dimethyl fumarate, methyl cinnamate, diben-zoylethylene, A -phenylmaleimide, and acenaphthylene. Alkynes such as dimethyl acetylenedicarboxylate also add to meso-ionic 1,3-dithiol-4-ones (134), but the intermediate cycloadducts are not isolable they eliminate carbonyl sulfide and yield thiophenes (137) directly. - ... 

The meso-ionic l,3>2-oxathiazol-5-ones (169) show an interesting range of reactions with nucleophiles including ammonia, primary amines, and aqueous alkali. They also react with l,3-dipolarophiles, including dimethyl acetylenedicarboxylate and methyl propiolate, yielding isothiazoles (171) and carbon dioxide. 1,3-Dipolar cycloaddition reactions with alkenes such as styrene, dimethyl maleate, and methyl cinnamate also lead to isothiazoles (171) directly. BicycUc intermediates (cf. 136) were not isolable these cycloaddition reactions with alkenes giving isothiazoles involve an additional dehydrogenation step. 

Methyl Cinnamate. Using lower temperature and pressure than those used by Falbe (5) (to avoid lactone formation) the selectivity of the reaction toward aldehydes and hydrogenated products was comparable with his. 

The reactions catalyzed by rhodium are quite different from those with cobalt. For example, the results with methyl 3,3-dimethacrylate indicate a destabilizing effect of the ester group, leading mainly to hydrogenolysis since isomerization occurs less readily with rhodium than with cobalt. Moreover, the nature and the position of the substituents seem to have little influence on the alkvlrhodiumcarbonyl stability. This attenuates the effect of the ester group, as shown by the results with methyl tiglate, methyl cinnamate, and ethyl 3-phenyl-2-butenoate. 

When the cluster [Pd4(C0)4(02CMe)4]-2MeC02H was dissolved in styrene and treated with methanol under an atmosphere of carbon monoxide, methyl cinnamate was formed.516 This reaction was also believed to occur by an alkoxycarbonyl route. The reaction became catalytic when [Pd(OAc)2] (106) was used in presence of NaOAc and a stoichiometric amount of copper(II) as reoxidant for the palladium(O) formed. Stille and co-workers have investigated this reaction, sometimes called carboalkoxylation, in detail. A basic difference between this reaction and the hydroesterification described above is that the oxidative nature of carboalkoxylation permits double functionalization of a double bond. Thus (E)- and (Z)-2-butene react readily with CO and methanol in the presence of a catalytic amount of PdCl2 and a stoichiometric amount of CuCl2 to give methyl 3-methoxy-2-methylbutanoate (equation 124).517,518... 

Keywords cyanoacetamide, malodinitril, methyl cyanoacetate, aromatic aldehyde, Knoevenagel condensation, solid-solid reaction, base catalysis, melt reaction, uncatalyzed, cinnamamide, cinnamonitril, methyl cinnamate... 

Although kinetic studies of bromination of methyl ( )-cinnamic acid and methyl (E)-fS-styrylphosphonate suggest analogous mechanisms for both reactions, the stereochemistry of the reactions indicates that product-forming steps of different character must be involved157. 

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