Acrolein cyclic acetal

Maeda and Yoshida (74) found that acrolein cyclic acetals (17-19) could be hydroformylated with cobalt carbonyl catalyst in benzene at 110°C and 200 atm of hydrogen and carbon monoxide. 

The hydroformylation of acrolein cyclic acetals has received considerable attention in the recent patent literature as a route to 1,4-butanediol (76-52). This diol is a comonomer for the production of polybutylene terephthalate, an engineering thermoplastic. The standard method for its manufacture has been from acetylene and formaldehyde, as shown in Eqs. (37) and (38) ... 

In contrast to the allyltitaniums derived from acrolein cyclic acetals, such as 1,2-dicyclo-hexylethylene acetal shown in Scheme 9.8, those derived from acrolein acyclic acetals react with ketones and imines exclusively at the y-position. As shown in Eq. 9.29, the reaction with chiral imines having an optically active 1-phenylethylamine moiety proceeds with high diastereoselectivity, thus providing a new method for preparing optically active 1-vinyl-2-amino alcohol derivatives with syn stereochemistry [53], The intermediate allyltita-nium species has also found use as a starting material for a carbozincation reaction [54],... 

The regiochemistry of hydroformylation of acrolein cyclic acetals can be controlled to some extent by the presence or absence of phosphine. Excess phosphine provides predominately the straight chain aide-... 

Addition of nucleophiles to both activated and unactivated alkenes is catalyzed by Pd(II). Addition of alcohols or AcOH to alkenes bearing EWGs is catalyzed by PdCl2(PhCN)2 to give the corresponding ethers and esters. The addition of an alcohol to the cyclic acetal of acrolein 82 to give the ether 83 is also possible with the same catalyst[64]. Amines add to the vinylic ether 84 to give 85, but not to simple alkenes[65]. 

In connection with studies on the ring-opening polymerization of cyclic acetals, we have undertaken investigations on the polymerization of bicyclic acetals, bicyclic oxalactone, and bicyclic oxalactam, which yield polysaccharide analogs, macrocyclic oligoesters, and a hydrophilic polyamide, respectively, some of which can be expected to be useful as novel speciality polymers. The monomers employed in the studies were prepared via synthetic routes presented in Scheme 1, starting from 3,4-dihydro-2H-pyran-2-carbaldehyde (acrolein dimer) I. 

The addition of certain glycols and polyols to acrolein leads to the production of cyclic acetal derivatives. 

Another type of compound having the furo-furanone skeleton, in which a C—C bond was formed at C-2 of 3, has been achieved by using 3 as a Michael carbanion donor to various a, 3-unsaturated carbonyl compounds. Thus, it gives 94a when combined with methyl vinyl ketone, which can then be converted to the cyclic acetal upon reaction with methyl alcohol in the presence of an acid (83T2137). The reaction was extended to acrolein, a-methyl acrolein, and crotonaldehyde to give 94c. Its application with 2-cyclohexen-l-one required an unexpected acid catalysis to give 94b. On the other hand, extending the reaction to a cyclic enedione,... 

Homoenolate and homoallenyl carbanion equivalents. Two routes to homo-cnolate species are based on the action of (propene)titanium diisopropoxide. Trialkoxy-titanates generated from acetals of acrolein react with aldehydes and imines. Chiral cyclic acetals are similarly cleaved to afford the nucleophiles. 3-Alkoxy-2-propyn-l-yl carbonates are transformed into (l-alkoxyallen)-l-yltitanates that add to carbonyl compounds with y-selectivity. ... 

A first approach described the use of catalyst 106a in the Michael reaction of a cyclic p-ketoester with acrolein (Scheme 5.28). ° The reaction proceeded satisfactorily, furnishing quantitatively the desired conjugate addition product in excellent enantioselectivity, requiring the in situ protection of the formyl moiety as the corresponding cyclic acetal derivative. However, the authors reported the need of a 9-fluorenyl ester Michael donor and the reaction was not studied further, with no data reported about the scope and limitations of the methodology. 

Diethyl chloroacetal refluxed with an equimolar amount of neopentyl glycol in the presence of 1 mole-% p-toluenesulfonic acid under a fractionating column with distillation of the resulting ethanol, benzene added when most of the ethanol has been removed after ca. 2 hrs., the remaining ethanol removed as benzene azeotrope, the catalyst destroyed with solid K-carbonate, and the product distilled 2-chloromethyl-5,6-dimethyl-m-dioxane. Y 95%. Numerous e., mostly m-dioxanes and other cyclic acetals, also direct acetalation of 0x0 compounds, e. g. acrolein, s. C. S. Rondestvedt, Jr., J. Org. Chem. 26, 2247 (1961) transaeetalation s. a. S. J. Angyal and R. M. Hoskinson, Soc. 1962, 2985 N. B.Lorette and W. L. Howard, Org. Synth. A2, 1 (1962). 

L-Ascorbic acid reacts as a Michael donor with acrolein or methyl vinyl ketone the products can be converted to cyclic acetals as shown in Scheme 5- The analogue (15) of ascorbic acid has been made as indicated in Scheme 6 the halogen at C-3... 

Considering only one example, an equimolar mixture of 22D and MA converts to a 100% yield of copolymer when heated in toluene for 2-3 h at 55-60°C, with 1.0 wt. % AIBN initiator. In the preparation, the solid polymer precipitates rapidly from the toluene after only a few minutes reaction time. Linear and cyclic acetals with vinyl unsaturation are easily prepared from acrolein and alcohols or glycols. Monomers such as acrolein diethylacetal... 

Cyclic 1,2-diketones, 24 594 Cyclic acrolein acetals, 2 271 Cyclic amidine curing agents, 10 410 Cyclic amidines, 10 412 Cyclic (aromatic disulfide) oligomers, 23 712... 

Cyclic acrolein acetals are, ill general, easily formed, stable compounds and have been considered as components in a variety of polymer systems. Table 6 lists a variety of previously prepared cyclic acrolein acetals and tlieir boiling points (69). 

This sequence has been used for the synthesis of 6-methoxymurrayanine (232) (Scheme 55) [214]. Reaction of butane-2,3-dione (226) with 4-methoxyphenyl isocyanate (227) to 4,5-dimethylene-3-(4-methoxyphenyl)-l,3-oxazolidin-2-one (228) followed by regioselective boron trifluoride-catalyzed Diels-Alder reaction with acrolein afforded the oxazolone 229. Only minor amounts of the undesired regioisomer were formed. Aromatization using 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) afforded the benzoxazol-2-one 230. Saponification of the cyclic carbamate and subsequent O-methylation led to the diarylamine 231. Finally, oxidative cyclization using stoichiometric amounts of palladium(ll) acetate provided 6-methoxymurrayanine (232). 

Among such oxidations, note that liquid-phase oxidations of solid paraffins in the presence of heterogeneous and colloidal forms of manganese are accompanied by a substantial increase (compared with homogeneous catalysis) in acid yield [3]. The effectiveness of n-paraffin oxidations by Co(III) macrocomplexes is high, but the selectivity is low the ratio between fatty acids, esters, ketones and alcohols is 3 3 3 1. Liquid-phase oxidations of paraffins proceed in the presence of Cu(II) and Mn(II) complexes boimd with copolymers of vinyl ether, P-pinene and maleic anhydride (Amberlite IRS-50) [130]. Oxidations of both linear and cyclic olefins have been studied more intensively. Oxidations of linear olefins proceed by a free-radical mechanism the accumulation of epoxides, ROOH, RCHO, ketones and RCOOH in the course of the reaction testifies to the chain character of these reactions. The main requirement for these processes is selectivity non-catalytic oxidation of propylene (at 423 K) results in the formation of more than 20 products. Acrylic acid is obtained by oxidation of propylene (in water at 338 K) in the presence of catalyst by two steps at first to acrolein, then to the acid with a selectivity up to 91%. Oxidation of ethylene by oxygen at 383 K in acetic acid in... 

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