Methyl cinnamates, addition

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. 

The combination of CsF with Si(OMe)4 58 is an efficient catalyst for Michael additions, e.g. of tetralone 130 to methacrylamide, followed hy cyclization of the addition product to the cyclic enamide 131 in 94% yield [67]. Likewise, addition of the lactone 132 to methyl cinnamate affords, after subsequent cyclization with tri-fluoroacetic acid, the lactam 133 in 58% yield [68] whereas < -valerolactam 134, with ethyl acrylate in the presence of Si(OEt)4 59/CsF, gives 135 in 98% yield [69]. Whereas 10mol% of CsF are often sufficient, equivalent amounts of Si(OEt)4 59 seem to be necessary for preparation of 135 [69] (Scheme 3.11). 

One of the distinguishing features of liverworts is their capacity to produce a variety of volatile, often very fragrant, oils that occur in oil bodies distributed over much of the surface of the organism. Several of these volatile compounds figure prominently in defining geographically different chemotypes in several countries. Toyota et al. (1997) examined 280 specimens of C. conicum collected at Kamikatsu-cho and Katsuura-cho, both Katsuura-gun, Tokushima. Three chemotypes were identified based upon their major components. Chemotype-I-accumulated (-)-sabinene [420], chemotype-II-accumulated (H-)-bomyl acetate [421], and chemotype III was characterized by methyl cinnamate [422] (see Pig. 5.4 for structures). In addition to a number of compounds known from previous studies of C. conicum, three... 

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]. 

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>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 is a colorless crystalline solid mp 36.5 °C) with a fruity, sweet-balsamic odor. In addition to the common esterification methods, it can be prepared by Claisen condensation of benzaldehyde and methyl acetate in the presence of sodium. Methyl cinnamate is used in soap perfumes, as well as in blossom and oriental perfumes, and is sometimes added to aromas. 

An alternative approach is the modification of heterogeneous catalysts by the addition of naturally occuring chiral molecules. The first example (H2) by Lipkin [17] might not be a real modified Pt catalyst because a stoichiometric amount of hydrocinchonine as salt of P-methyl-cinnamic acid was used. Nakamura [18] and later Isoda [22] and Izumi [4] chose chiral acids to... 

Cabaleiro and Johnson (1967) report that the addition of chlorine to -methyl cinnamate in chloroform or acetic acid is syn-selective, SS 0-75, in chloroform and acetic acid acetoxychloro derivatives are produced as well. Again, Dewar and Fahey (1964) argue that the normal course of addition of hydrogen halides onto olefins is a polar electrophilic process involving classical carbonium ions as intermediates and leading mostly but not exclusively to cis-adducts. A syn-preference was found in the additions of deuterium bromide to acenaphthylene, indene, and cis- and fraws-phenylpropene. In the case of indene, phenylpropene and methyl cinnamate, which are styrene analogs, concerted syn addition is symmetry-allowed (see bottom of p. 273). 

As shown in Scheme 3, (Z)-enolate (57), prepared by conjugate addition of lithium bis(phenyldi-methylsilyl)cuprate to methyl crotonate or methyl cinnamate, reacts with acetaldehyde or benzaldehyde to give a mixture of two diastereomeric aldols, (58) and (59), with excellent diastereomeric excess favoring (58) (ratios of 85 15 to 94 6). On the other hand, deprotonation of ester (60) by LDA provides the ( )-enolate (61), which reacts with the same two aldehydes to give the aldol (59) as the major product... 

Note 3). To this stirred solution is added dropwlse through the dropping funnel butylllthium In hexane (Note 4) (1.60 M, 55 mL, 88 nmol), transferred by syringe, at such a rate that the temperature does not rise above 20°C (about 10 min). When the addition Is complete, the methyl ester [either methyl cinnamate (Note 5) (16.21 g, 100 mmol) or methyl nicotinate (Note 5) (13.71 g, 100 nmol)], dissolved in 30 nt of tetrahydrofuran, is added In one... 

It stands out that the photochemistry is also dependent of the crystalline phases where the topochemical relations between nearest-neighbor molecules are not the same in the pure guest crystals and in the TOT clathrates. When the TOT/cw-stilbene clathrate was irradiated, photoconversion to trans-stilbene occurred smoothly with the additional formation of small amounts of phenanthrene and of an unidentified product. On the contrary the TOT/tru j-stilbene clathrate remained unchanged when irradiated for long periods of time. In the majority of cases, crystalline cw-cinnamic acid derivatives are entirely converted to tran -isomers on irradiation and the trans-to-cis isomerization is not observed However both TOT clathrates with the trans- and cis-isomers of methyl cinnamate photoisomerized under similar conditions. It is noteworthy that these clathrates and those of the stilbenes (Sect. 2.1.4) are isomorphous. 

Plum flavor An important factor is the correct quantitative ratio of a few major components such as linalool, benzaldehyde, methyl cinnamate (see cinnamic acid), 2-phenylethanol, and 4-decanolide (see alkanolides), in addition to green notes such as (Z)-3- -hexen-l-ols and 2- hexenals, as well as fruit esters, e. g., ethyl octanoate. 

TABLE 5.20. Influence of Additive and Slow Addition of Methyl Cinnamate on the ee in the Asymmetric Dihydroxylation Reaction of Methyl Cinnamate"... 

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