Aldehydes isobutyraldehyde

Chemical Designations - Synonyms Isobutyric Aldehyde Isobutyraldehyde Isobutylaldehyde 2-Methylpropanal Chemical Formula (CH3)2CHCHO. 

The only reactions in Table 1 where diastereoselectivity deviates markedly from the reagent isomeric purity involve the (Z)-7-alkoxyallylboronates (entries 21-26), and then only when a sterically demanding aldehyde (isobutyraldehyde, entries 24-26) or a bulky protecting group is employed. Under these circumstances it appears that boat-like transition state (13) becomes competitive with the otherwise favored chair arrangement (12 Figure 7). 

Epoxidation The epoxidation of alkenes can be effected with molecular oxygen and an aldehyde. Isobutyraldehyde and pivaldehyde are the most effective. Note that a metal catalyst is not involved. Yields are highest when the ratio of alkene to aldehyde is 1 3. 

Synonyms iBuH Isobutanal Isobutyl aldehyde Isobutyraldehyde Isobutyric aldehyde 2-Methyl-1 -propanal 2-Methylpropionaldehyde Valine aldehyde... 

Synonyms Isobutyric Aldehyde Isobutyraldehyde Isobutylaldehyde 2-Methylpropanal Chemical Formula (CHjljCHCHO (ii) Observable Characteristics — Physical State (as normally shipped) Liquid Color Colorless Odor Pungent (iii) Physical and Chemical Properties — Physical State at 15 "C and I atm. Liquid Molecular Weight 72.11 Boiling Point at I atm. 147, 64.1, 337.3 Freezing Point -112, -80, 193 Critical Temperature 464, 240, 513 Critical Pressure 600, 41, 4.2 Specific Gravity 0.791 at 20 C (liquid) Vapor (Gas) Density 2.5 Ratio of Specific Heats of Vapor (Gas) ... 

Aldehydes fiad the most widespread use as chemical iatermediates. The production of acetaldehyde, propionaldehyde, and butyraldehyde as precursors of the corresponding alcohols and acids are examples. The aldehydes of low molecular weight are also condensed in an aldol reaction to form derivatives which are important intermediates for the plasticizer industry (see Plasticizers). As mentioned earlier, 2-ethylhexanol, produced from butyraldehyde, is used in the manufacture of di(2-ethylhexyl) phthalate [117-87-7]. Aldehydes are also used as intermediates for the manufacture of solvents (alcohols and ethers), resins, and dyes. Isobutyraldehyde is used as an intermediate for production of primary solvents and mbber antioxidants (see Antioxidaisits). Fatty aldehydes Cg—used in nearly all perfume types and aromas (see Perfumes). Polymers and copolymers of aldehydes exist and are of commercial significance. 

Manufacture and Processing. 2,2,4-Trimethyl-l,3-pentanediol can be produced by hydrogenation of the aldehyde trimer resulting from the aldol condensation of isobutyraldehyde [78-84-2]. 

The principal commercial source of 1-butanol is -butyraldehyde [123-72-8] obtained from the Oxo reaction of propylene. A mixture of n- and isobutyraldehyde [78-84-2] is obtained in this process this mixture is either separated initially and the individual aldehyde isomers hydrogenated, or the mixture of isomeric aldehydes is hydrogenated direcdy and the n- and isobutyl alcohol product mix separated by distillation. Typically, the hydrogenation is carried out in the vapor phase over a heterogeneous catalyst. For example, passing a mixture of n- and isobutyraldehyde with 60 40 H2 N2 over a CuO—ZnO—NiO catalyst at 25—196°C and 0.7 MPa proceeds in 99.95% efficiency to the corresponding alcohols at 98.6% conversion (7,8) (see Butyraldehydes Oxo process). 

The infrared carbonyl stretching frequencies of n- and isobutyraldehyde in the condensed phase occur at 1727.6 and 1738.0 cm , respectively (38). The proton nmr spectra of both aldehydes are weU-known (39). 

The total 1988 woddwide volumes of n- and isobutyraldehyde were 4.3-4.4 x 10 t and 7.7 x 10 t, respectively. The merchant market for the two aldehydes is relatively insignificant, most of the production being employed captively. The principal U.S. producers of butanals are given in Table 4. The principal producers in Western Europe and Asia are given in Table 5. 

Enamines derived from aldehydes disubstituted on the jS carbon such as those derived from isobutyraldehyde (16) are alkylated on nitrogen by alkyl... 

More recently the acylation of aldehyde enamines has been reinvestigated (75) and shown to proceed normally when the enamine is added to the acid chloride. The morpholine enamine of isobutyraldehyde (98), on being added to an ether solution of acetyl chloride, afforded the iminium salt (99), from which the ketoaldehyde (100) was obtained in 66% yield by hydrolysis (75). 

Likewise, enolizable aldehydes such as isobutyraldehyde or 2-phenacetaldehyde are converted by silylated morpholine 294, in the presence of TMSOTf 20, into N,N-acet-als such as 466 in nearly quantitative yield [57]. The thermal and, in particular, Lewis acid-catalyzed conversion of 0,N-acetals such as 124 into N,N-acetals such as 464a obviously proceeds via the intermediate 467 and iminium salts such as 468, which readily add nucleophiles, as discussed in Sections 5.1.3 and 5.2 (Scheme 5.20). 

The disilanickela complex 21 was also found to be a good catalyst for the dehydrogenative double silylation of aldehydes. The nickel-catalyzed reactions of 1,2-bis(dimethylsilyl)carborane 11 with aldehydes such as isobutyraldehyde, trimethylacetaldehyde, hexanal, and benzaldehyde afforded 5,6-carboranylene-2-oxa-l,4-disilacyclohexane.32 34 36 The dehydrogenative 1,4-double silylation of methacrolein and tram-4-phenyl-3-buten-2-one in the presence of a catalytic amount ofNi(PEt3)4 also took place under similar conditions. In contrast, the reaction of 11 with a-methyl-tran.s-cinnamaldehyde and irans-cinnamaldehyde under... 

Sulfur ylides are a classic reagent for the conversion of carbonyl compounds to epoxides. Chiral camphor-derived sulfur ylides have been used in the enantioselective synthesis of epoxy-amides <06JA2105>. Reaction of sulfonium salt 12 with an aldehyde and base provides the epoxide 13 in generally excellent yields. While the yield of the reaction was quite good across a variety of R groups, the enantioselectivity was variable. For example benzaldehyde provides 13 (R = Ph) in 97% ee while isobutyraldehyde provides 13 (R = i-Pr) with only 10% ee. These epoxy amides could be converted to a number of epoxide-opened... 

The principal product of the hydroformylation which is most desired in industrial applications is a linear aldehyde. The unmodified, cobalt-catalyzed processes produce a mixture of linear and branched aldehydes, the latter being mostly an a-methyl isomer. For the largest single application—propylene to butyraldehydes—the product composition has an isomer ratio (ratio of percent linear to percent branched) of (2.5 t.0)/l. The isobutyraldehyde cannot be used to make 2-ethylhexanol, and iso-... 

The catalyst formed in this manner exhibited carbonyl infrared absorptions, as shown in Table XXX. These catalysts were tested by hydroformylation of ethylene or propylene at 100°C and atmospheric pressure. Both were effective, with (A) being better than (B), probably because of the higher surface area. The aldehyde formed from propylene was a mixture of 63% n- and 37% isobutyraldehyde. The rate expression for ethylene hydroformylation was ... 

The kinetics of the ionic hydrogenation of isobutyraldehyde were studied using [CpMo(CO)3H] as the hydride and CF3C02H as the acid [41]. The apparent rate decreases as the reaction proceeds, since the acid is consumed. However, when the acidity is held constant by a buffered solution in the presence of excess metal hydride, the reaction is first-order in acid. The reaction is also first-order in metal hydride concentration. A mechanism consistent with these kinetics results is shown in Scheme 7.8. Pre-equilibrium protonation of the aldehyde is followed by rate-determining hydride transfer. 

The supported Co2+-substituted Wells-Dawson POM, Cs6H2[P2W17061Co(OH2)], on silica was stable up to 773 K and catalyzed the heterogeneous oxidation of various aldehydes to the corresponding carboxylic acids with 02 as a sole oxidant [116], The H5PV2Mo10O40 POM, impregnated onto meso-porous MCM-41, catalyzed the aerobic oxidation of alkanes and alkenes using isobutyraldehyde as a... 

Carreira and co-workers developed a highly efficient enantioselective addition of terminal alkynes to aldehydes giving propargyl alcohols by the mediation of zinc tri-flate and N-methylephedrine [17]. This reaction serves as a convenient and powerful synthetic route to a wide variety of enantioenriched allenes via propargyl alcohols. Dieter and Yu applied this alkynylation to the asymmetric synthesis of allenes (Scheme 4.12) [18]. Reaction of phenylacetylene with isobutyraldehyde afforded the propargyl alcohol in 80% yield with 99% ee, which was mesylated to 49 in quantitative yield. Reaction of 49 with the cyanocuprate 50 afforded the desired allene 51 with 83% ee. 

The effect of cryptands on the reduction of ketones and aldehydes by metal hydrides has also been studied by Loupy et al. (1976). Their results showed that, whereas cryptating the lithium cation in LiAlH4 completely inhibited the reduction of isobutyraldehyde, it merely reduced the rate of reduction of aromatic aldehydes and ketones. The authors rationalized the difference between the results obtained with aliphatic and aromatic compounds in terms of frontier orbital theory, which gave the following reactivity sequence Li+-co-ordinated aliphatic C=0 x Li+-co-ordinated aromatic C=0 > non-co-ordinated aromatic C=0 > non-co-ordinated aliphatic C=0. By increasing the reaction time, Loupy and Seyden-Penne (1978) showed that cyclohexenone [197] was reduced by LiAlH4 and LiBH4, even in the presence of [2.1.1]-cryptand, albeit much more slowly. In diethyl ether in the absence of... 

It not tertiary, the product yield is lowered by transfer of the carbinol hydride ion to the aldehyde to produce a new alkoxide and an enolate ion. Thus, propylene oxide, after reductive cleavage with LDBB and trapping with isobutyraldehyde or p-anisaldehyde, provided 5-methyl-2,4-hexanediol in 40-50% yield or 1-p-anisyl-1,3-butanediol in 44% yield, respectively (in both cases about equal mixtures of diastereoisomers were obtained). The cyclohexene oxide-derived dianion, when trapped with isobutyraldehyde, gave 2-(1-hydroxy-2-methylpropyl)cyclohexanol in 71% yield as a mixture of only partially separable isomers in the ratio 15 11 39 35. 

With a branched aldehyde, such as isobutyraldehyde 78, the selectivity of the reaction is very high (76 72 > 100 1 Table 9.5), even with the less selective (but more reactive) boron enolate (5)-74a. 

Another process mechanistically related to imine exchange is the dynamic production of pyrazolotriazinones reported in 2005 by Wipf and coworkers [29]. After first verifying that reaction of either 16 or 17 with equimolar quantifies of isobutyraldehyde and hydrocinnamaldehyde at 40°C in water (pH 4.0) resulted in the same 3 7 mixture of 16 and 17 at equilibrium (Fig. 1.6, Eq. 1), the authors demonstrated that a library could be generated by reaction of pyrazolotriazinone 16 with a series of aldehydes (Fig. 1.6, Eq. 2). Direct metathesis of pyrazolotriazinones was also demonstrated, as was reaction with ketones. Importantly, equilibration was halted by raising the pH to 7. 

Aldehydes acetaldehyde, benzaldehyde, formaldehyde, glyoxal, isobutyraldehyde, trichloroaldehyde... 

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