Benzaldehydes acrylate reaction

The solvent-less UV printing systems use acrylate monomers with a photo initiator such as benzophenone. The acrylate monomers are polymerized under UV light to form a hard, dry print. Residual odors in this printing system would likely come from unpolymerized acrylate, reaction byproducts, and residual benzophenone. Benzophenone has a geranium-like odor. Potential byproducts that may taint a food include benzaldehyde and alkyl benzoates. 

It is supposed that the nickel enolate intermediate 157 reacts with electrophiles rather than with protons. The successful use of trimethylsilyl-sub-stituted amines (Scheme 57) permits a new carbon-carbon bond to be formed between 157 and electrophiles such as benzaldehyde and ethyl acrylate. The adduct 158 is obtained stereoselectively only by mixing nickel tetracarbonyl, the gem-dibromocyclopropane 150, dimethyl (trimethylsilyl) amine, and an electrophile [82]. gem-Functionalization on a cyclopropane ring carbon atom is attained in this four-component coupling reaction. Phenyl trimethyl silylsulfide serves as an excellent nucleophile to yield the thiol ester, which is in sharp contrast to the formation of a complicated product mixture starting from thiols instead of the silylsulfide [81]. (Scheme 58)... 

Phosphonium salts have also been used as co-catalysts in the DABCO catalyzed Baylis-Hillman reaction of methyl acrylate with benzaldehyde [122]. Good results were obtained with triethyl-n-butylphosphonium tosylate with up to quantitative yields in some cases. The authors proposed that the phosphonium salt is rather stabilizing the intermediate 50, shown in Scheme 48, and increasing therefore its concentration rather than activating the benzaldehyde. 

Figure 6.7 Hydrogen-bonding (thio)ureas screened in the DABCO-promoted MBH reaction between benzaldehyde and methyl acrylate the pseudo-first-order rate constants relative to the uncatalyzed reaction are given in h . ...

Figure 6.8 Proposed modes of action of hydrogen-bonding catalyst 16 Bidentate hydrogen bonding coordination of the zwitterion derived from Michael-type DABCO attack to methyl acrylate (1) and Zimmerman-Traxler transition state for the reaction of methyl acrylate with benzaldehyde (2).

The simultaneous use of urea, or thiourea [76] and DABCO catalyst was introduced by the Connon group for the addition of methyl acrylate and benzaldehyde [39]. The study revealed that, although both ureas and thioureas accelerated the reaction relative to the uncatalyzed process, urea was superior to thiourea in terms of stability and efficiency. Chiral thiourea derivatives may offer, however, superior enantioselectivity. It was postulated, that the catalysts operate mainly via a Zimmerman-Traxler-type transition state 69 for addition of the resulting enolate anion to the aldehyde (Scheme 5.15). 

Scheme 5.15 DABCO and urea, 68-promoted MBH reaction of benzaldehyde and methyl acrylate.

A one-step construction of y,y-difunctionalized y-butyrolactones from benzoins or benzaldehydes via a tandem reaction promoted by l,3-dimethyl-imidazol-2-ylidene in the presence of methyl acrylate was reported by Zhai et al. [63]. So far, the exact mechanism of the reaction, as well as the role of the catalyst, has not been clarified. 

Figure 2 Selectivity at 30% conversion for the reactions indicated as a function ofD°H C-H(reactant) - D°HC-h or c-c (product). 1 ethylbenzene to styrene 2. 1-butene to 1, 3-butadiene 3. toluene to benzoic acid 4. acrolein to acrylic acid 5. ethane to enthylene 6. n-butane to maleic anhydride 7. benzene to phenol 8. toluene to benzaldehyde 9. propene to acrolein 10. 1-butene to 2-butanone 11. isobutene to isobutene 12. methanol to formaldehyde 13. methacrolein to methacyclin acid 14. propane to propene 15. ethanol to acetaldehyde 16. isobutene to methacrolein 17. n-butane to butene 18. benzene to maleic anhydride 19. propane to acrolein 20. methane to ethane 21. ethane to acetaldehyde, 22. isobutane to methacrylic acid 23. methane to formaldehyde 24. isobutane to methacrolein.

Starting from (Z)-l,2-dimethoxyethene, the Z-isomer of 1,2-dimethoxyvinyl anion was prepared by deprotonation with the Lochmann-Schlosser base at — 78 °C, being trapped with methyl chloroformate to provide the acrylate 579857 (Scheme 157). This compound was further lithiated at the /i-position to give a /LacyI vinyllithium858 which, after reaction with benzaldehyde, was transformed into the a./Lbulenolide 580. 

Phenylmenthyl acrylate has been used as a component in an asymmetric Baylis-Hillman reaction. Treatment of the acrylate with 1,4-Diazabicyclo[2.2.2]octane and benzaldehyde at 8 kbar of pressure delivers the a-(hydroxyalkyl)acrylate (eq 8). The product obtained has an 86% de. Menthyl acrylate is superior to the phenylmenthyl acrylate in this particular application. In a radical-mediated addition, phenylmenthyl acrylate gives rise to the a-pyridyl sulfide in 68% yield (eq 9). The final product is isolated with a 56% de. 

Protonation becomes a rapid reaction in protic solvents and in the presence of acids, as demonstrated for, e.g., -butyl acrylate in aqueous solution [207], methyl acrylate in EtOH [208], cinnamates in the presence of phenol in DMF [209], and benzaldehyde in ethanolic buffer solution [210]. Rate constants for protonation of aromatic radical anions (anthracene [211], naphthalene, 2-methoxynaphthalene, 2,3-dimethoxynaphthalene) by a number of proton donors including phenols, acetic acid, and benzoic acids in aprotic DMF were found to vary from 5.0 X 10 M- s-> (for anthracene, in the presence of p-chlorophenol) to 6.2 x lO s (for anthracene, in the presence of pentachlorophenol) [212]. For dimedone, PhOH, or PhC02H the rate of protonation depends on the hydrogen-bond basicity of the solvent and increases in the order DMSO < DMF MeCN [213],... 

Reaction conditions A MeOH (1 equiv.) B CuCN (1 equiv.) C ethyl 2-(bromomethyl)acrylate D nitrostyrene E MeaSnCI (1 equiv.) F allyl bromide G i-BuOH (1 equiv) (E)-1-iodo-l-butene, Pd(PPh3) cat I CITi(OiPr)3 (2 equiv.), benzaldehyde (1.5 equiv.). 

In an important achievement Vo-Thanh and co-workers realized that chiral ionic liquids such as 35 can act as chiral inducers for the asymmetric MBH reaction.The V-octyl-V-methylephedrinium trifluoromethanesulfonate salt 35, used as solvent in the DABCO-mediated reaction of methyl acrylate and benzaldehyde, produced the corresponding allylic alcohol in 60% yield and 44% ee after 7 days at 30 °C. 

Some chiral ILs have been designed and synthesized. They have already been applied in different fields snch as asymmetric synthesis, stereoselective polymerization, chiral chromatography, liquid crystals, chiral resolution, and NMR shift reagents [20,106, 107]. Chiral solvents have been reported in asymmetric syntheses. In the BayUs-HUlman reaction of benzaldehyde and methyl acrylate in the presence of bases, chiral ILs demonstrate their ability in the transfer of chirality, even if the enantiomeric excesses (ee) are stiU moderate. The presence of an alcoholic functional group on the Af-alkyl-fV methylephedrinium is primordial and acts as a fixing point of the chiral IL on the reactants. It is assumed that the OH is connected... 

Notable new general syntheses of butenolides include the addition of the three-carbon synthon Li(PhS)C=CMeC02Me to aldehydes R CHO (R = alkyl or aryl) to yield the thioethers (19), the related reaction of lithio-j8-lithio-acrylates R CLi=CR C02Li with benzaldehyde to give compounds (20 R = H or Me), and the formation of (21) from the iodinated allyl alcohol ICMe=CHCH20H and carbon monoxide in the presence of bis(triphenylphos-phine)palladium(ii) chloride. Chloral reacts with dimethyl (benzylamino)fu-marate to yield the butenolide (22), whereas aromatic aldehydes give hydroxy-pyrrolinones (23). The total synthesis of piperolide (24) has been reported. 

There are several examples of investigations of oxidation processes, involving radiotracers. Many substances can be partially oxidized by O2, if selective catalysts are used to control kinetically the oxidation process, otherwise the partial oxidation products will react further resulting in total combustion to CO2 and H2O. It is possible to introduce O2 into hydrocarbons such as olefins and aromatics to synthesize aldehydes (for example, acrolein and benzaldehyde) and acids (for example, acrylic acid, phthalic acid anhydride). In some reactions a selective oxidation can also result in dehydrogenation (butene butadiene) or dealkylation (toluene benzene) processes. 

In a dry flask were added 855 mg tosylamide (5 mmol), 84 mg DABCO (0.75 mmol), and 58.5 mg La(0Tf)3-H20 (0.1 mmol) together with 900 mg 4-A molecular sieves. Then 2.5 mL wo-PrOH, 505 fiL benzaldehyde (5 mmol), and 450 /u-L methyl acrylate (5 mmol) were added, and the reaction mixture was stirred for 48 h at ambient temperature. The mixture was Altered through a thin layer of Celite, which was rinsed three times with 10 mL wo-PrOH. The solvent was evaporated, and to the crude mixture were added 25 mL methanol and 10 mL 1 M sulfuric acid. The solution was stirred for 1 h, and then methanol was evaporated. The remaining acidic solution was diluted with water and extracted with dichloromethane (3 x 30 mL). The organic phase was then successively washed with saturated NaHCOs, 1 M NaOH, water, and saturated NaCl solution and dried over Na2S04. Evaporation of the solvent gave 1.38 g pure methyl Q -methylene-)8-[(/ -toluenesulfonyl)-amino]-3-phenylpropionate as a white crystalline material, in a yield of 80%, m.p. 76-77°C. 

In a series of additions of benzaldehyde to alkyl acrylates, it clearly appeared that the reaction rate decreased with steric bulk and with chain length of the alcohol, probably due it impeding the approach of the reagents (Scheme 1.9). The latter effect may also be steric in nature if the chain folded back on itself, or it could be a consequence of a less polar reaction medium since the reactions were carried out with a 30% excess of acrylate and without a solvent. 

Formation of cyclic acetals was also observed in the MBH reaction of aliphatic aldehydes with pantolactone acrylate 28. The more stable cis isomers 29 are formed predominantly, and mixed products 30 can be isolated by sequential addition of two different aldehydes (Scheme 1.14). However, benzaldehyde failed to give the cyclic adduct on reaction with the pantolactone ester under the same conditions electronic effects rather than steric hindrance... 

In the DABCO-catalyzed MBH reaction between aromatic or heteroaromatic dialdehydes 107 with methyl acrylate, mono-adduct 108 can be obtained selectively in excellent yields the rate of the first condensation of a carbonyl group is considerably increased by the electron-withdrawing effect of the second carbonyl group (compare with the condensation rate of benzaldehyde), and of course the second condensation was considerably slowed. However, upon increasing the amount of used methyl acrylate, diadducts 109 and no were also obtained in moderate to good yields (Scheme 1.52). With orthophthalaldehyde, cyclic hemiacetals 111 were the sole product (Scheme 1.52). ... 

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