Acrolein, dimethyl acetal

The P-alkoxy elimination pathway is important during the incorporation of oxygen-containing monomers. Therefore, it is often necessary to provide distance between the olefin and the polar group, or to prevent chain walking close to the group that can be eliminated by the placement of a quaternary carbon spacer [87], The incorporation of acrolein dimethyl acetal is accompanied by reduced activity and full catalyst... 

Aconitic acid, p206 Acrolein, p203 Acrolein diethyl acetal, d312 Acrolein dimethyl acetal, d521 Acrylaldehyde, p203... 

Ethyl diazoacetate (22.8 g, 0.20 mol) is added at a rate of 1.5 mL h" to a stirred mixture of acrolein dimethyl acetal (40.8 g, 0,40 mol) and rhodium(Il) acetate (0.44 g, 0.001 mol, 0.5%), keeping the temperature of the reaction mixture at 20 °C. The mixture is then filtered through a short column of neutral alumina which is washed with ether. Distillation of the combined filtrates yields 19.2 g of a fraction (bp 107-112 °C, 13 Torr) consisting of 93% of the title compound (47% yield) and 7% of the cyclopropanation product. 

A very useful three-carbon olefin is acrolein dimethyl acetal (5). Acrolein itself cannot be used because it polymerizes and/or reacts with amines under the normal reaction conditions. With piperidine or morpholine as the base, acrolein acetals react in good yield with a wide variety of vinylic bromides to give dienal acetals and/or ami-noenal acetals. These product mixtures, after being treated with excess aqueous oxalic acid and being steam distilled, yield E,E-conjugated dienals, usually in good yields. Methacrolein acetals and 3-buten-2-one ethylene ketal also react well, but the crotonaldehyde acetals do not. 

Acrolein dimethyl acetal, d454 Acrylaldehyde, p207... 

The Pd(0)-catalyzed allylation of 96 with acrolein dimethyl acetal gives exclusively compound 104. The 7j3-allylpalladium cationic complex (4, R = OMe) is attacked only at the center bearing the substituent MeO (80SC147), thus emphasizing the importance not only of steric effects in the electrophile but also of the electronic effects in the Tsuji-Trost reaction (92T1695). Indole 96 has been also allylated with epoxide 105 under Pd(0) catalysis by Trost and Molander (81JA5969). The intermediate cationic complex is attacked at the exocyclic position, 106 being formed, as shown in Scheme 22. 

Figure 6-28 Left The and spectra of the dimethyl acetal of acrolein. Right The normal HETCOR (called HSC, bottom) and the H-H-C relay coherence transfer (top) experiments for the same molecule. (Reproduced from A. E. Derome, Modern NMR Techniques for Chemistry Research, Pergamon Press, Oxford, UK, 1987, p. 257.)...

Regiospecific alkylation of dimethylhydrazone anions with the masked acrolein equivalent, 3-bromo-propionaldehyde dimethyl acetal, has brcn used as an alternative to a conventional Michael reaction in Corey s total synthesis of picrotoxinin (c/. equation 13). Azaallyllithium reagents derived from aldehyde and ketone hydrazones, unlike enolates, yield monoalkylation products with control of both regio-chemistry and stereochemistry. In appropriate cases, alkylation followed by deprotection to form a dicarbonyl product can be a very effective synthetic strategy. 

When acrolein is allowed to react with HBr at —15° in the presence of methanol, the bromine adds primarily at the 3-position although the end-product is 1,3-dibromopropyl methyl ether the latter affords 3-bromopropanal dimethyl acetal when kept in methanol for 12 hours.206... 

ETHYLENE GLYCOL ETHYL MERCAPTAN DIMETHYL SULPHIDE ETHYL AMINE DIMETHYL AMIDE MONOETHANOLAMINE ETHYLENEDIAMINE ACRYLONITRILE PROPADIENE METHYL ACETYLENE ACROLEIN ACRYLIC ACID VINYL FORMATE ALLYL CHLORIDE 1 2 3-TRICHLOROPROPANE PROPIONITRILE CYCLOPROPANE PROPYLENE 1 2-DICHLOROPROPANE ACETONE ALLYL ALCOHOL PROPIONALDEHYDE PROPYLENE OXIDE VINYL METHYL ETHER PROPIONIC ACID ETHYL FORMATE METHYL ACETATE PROPYL CHLORIDE ISOPROPYL CHLORIDE PROPANE... 

Conversion of the Adduct from Bromine and Acrolein into the Dimethyl and Diethyl Acetal... 

Proton affinity (PA) acetaldehyde, 123 acetone, 123 acrolein, 123 butenone, 123 dimethyl ether, 123 dimethylacrolein, 123 formaldehyde, 123 methanol, 123 methyl acetate, 123 methyl acrylate, 123 (Aj-mcthylacrolein, 123 oxetane, 123 table of, 123 tetrahydrofuran, 123 water, 123... 

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