Benzaldehyde butanone

V-Acylation of oxaziridine (54) is of more importance, yielding 2-acyloxaziridines which were unaccessible otherwise until recently. Oxaziridines (54) derived from cyclohexanone, butanone or benzaldehyde are acylated readily by acetic anhydride, acid chlorides or isocyanates. Oxaziridines from aliphatic aldehydes, too unstable to be isolated, may be trapped in situ by benzoylation (67CB2593). 

C Nuclear magnetic resonance spectrum, acetaldehyde, 732 acetophenone, 732 anisole, 672 benzaldehyde, 732 benzoic acid, 771 p-bromoacetophenone, 449 2-butanone, 449, 732 crotonic acid. 771 cyclohexanol, 634 cyclohexanone, 732 ethyl benzoate, 477 methyl acetate, 443 methyl propanoate, 450 methyl propyl ether, 672... 

Surprisingly, the size of the silyl protecting group significantly influences the stereochemical outcome of aldol additions performed with the lithium enolates of (S )-l-trimethylsiloxy-and (S)-l-f< rt-butyldimethylsiloxy-l-cyclohexyl-2-butanone. Thus, the former reagent attacks benzaldehyde preferably from the Si-face (9 1), which is the opposite topicity to that found in the addition of the corresponding titanium enolates of either ketone ... 

The chlorotitanium enolate, generated by treatment of (S )-l-tm-butyldimethylsiloxy-l-cyclohexyl-2-butanone with titanium(iv) chloride and diisopropylethylamine, provides the syn-product upon reaction with benzaldehyde. The diastereoselectivity of 99 1 is defined as the ratio of the major isomer to the sum of all other isomers47bc. 

The two established Hnls, those from L. usitatissimum and P. amygdalus, have found biocatalytic applications for the production of (i )-cyanohydrins. The former of these Hnls is the least widely applied, the natural substrates being acetone cyanohydrin or (i )-2-butanone cyanohydrin (Table 1) [28]. Although an improved procedure for the purification of this enzyme has been reported [27] it is still only available in limited quantities (from 100 g of seedlings approximately 350 U of enzyme are obtained). It was found that this enzyme transforms a range of aliphatic aldehyde and ketone substrates [27], the latter of which included five-membered cyclic (e.g. 2-methylcyclopentanone) and chlorinated ketone substrates. In contrast, attempts to transform substituted cyclohexanones and 3-methylcyclopentanone failed and it was even found that benzaldehyde deactivated the enzyme. 

Iridium nanoparticles generated in l-n-butyl-3-methylimidazolium (BMI)-based ionic liquids were found to be excellent recyclable catalytic systems for the hydrogenation of a variety of substrates, including ketones such as simple ketones. The Ir nanoparticles were prepared by simple reduchon of [Ir(cod)Cl]2 dispersed in BMI-PFis at 75 °C under 4 atm of H2. Benzaldehyde, cyclopentanone, methyl butanone and derivatives were hydrogenated with almost complete conversion, with TOFs ranging from 17 to 96h under solventless conditions (substrate Ir ratio = 250, 75 °C, 4 atm FI2) [102]. 

Eq. 59), and even surprisingly high for aliphatic ketones such as 2-butanone, a substrate that offers very little steric discrimination (Eq. 60). Reagent 74 is less effective than 70 in allylations of aldehydes (e.g., 90% ee vs. >98% ee for 70 in the allylation of benzaldehyde). The superior reactivity and selectivity of 74 with ketones is ascribed in part to the lesser steric bulk of the phenyl substituent compared to the trimethylsilyl unit of reagent 70. The smaller phenyl substituent of 74 would provide a better fit for ketones in the chiral pocket of the reagent. 

Additional insight into the factors affecting product structure was obtained by study of the condensation of 2-butanone with benzaldehyde.2... 

The results indicate that the product ratio is determined by the competition between the various reaction steps. Under base-catalyzed conditions, 2-butanone reacts with benzaldehyde at the methyl group to give l-phenylpent-l-en-3-one. Under acid-catalyzed conditions, the product is the result of condensation at the methylene group, namely, 3-methyl-4-phenylbut-3-en-2-one. Under the reaction conditions used, it is not possible to isolate the intermediate ketols, because the addition step is rate-limiting. These intermediates can be... 

Particleboard Formaldehyde, acetone, hexanal, propanol, butanone, benzaldehyde, benzene... 

Problem 15.41 Which alkenes are formed from the following ylide-carbonyl compound pairs (a) 2-butanone and CH,CH2CH2CH=P(C H,)j. (b) acetophenone and (CftH,)3P==CH2, (c) benzaldehyde and... 

Oxaziridines unsubstituted at nitrogen (9, R =H) (in general used as aminating reagents, see Sections 3.5.4 and 3.5.6), are prepared by treatment of carbonyl compounds with chloramine or hydroxylamine-O-sulfonic acid in aqueous media (91S327). This method is, however, limited to certain carbonyl compounds with cyclohexanone, followed by butanone, benzaldehyde, and trichloroacetaldehyde giving the best results. 

Favorskii-type reactions, which are known to be sensitive to the base and solvent used and to the nature of the halogen leaving group, continue to attract attention, and in combination with other bond forming processes can often be manipulated to provide useful synthetic methods. For example, the chloroketone 1 gives pivalic acid on treatment with 40% aqueous NaOH, but only 3-hydroxy-3-methyl-2-butanone on reaction with either 20% aqueous Na2CC>3 or 14% aqueous or ethanolic KOH. When a mixture of 1 (3.5 eq.) and benzaldehyde (1 eq.) was treated with 14% ethanolic KOH (7 eq.) at room temperature for 3 hours, however, the lactone 2 was the major... 

Formaldehyde, acetaldehyde, acetone, propionaldehyde, cro-tonaldehyde, methacrolein, 2-butanone, butyraldehyde, benzaldehyde, valeraldehyde, p-tolualdehyde, hexaldehyde... 

What products are obtained from the reaction between benzaldehyde and butanone in the presence of base (NaH, room temperature) Draw the structural formulae of all of the reaction products in spatially correct Newman projections. Chose the conformation in which the phenyl and carbonyl groups are antiperiplanar to one another. 

In the aldol reaction between butanone and benzaldehyde it is important to note that butanone can form more than one enolate. Under the reaction conditions given, formation of the more substituted and thermodynamically more stable enolate will be produced, and this can be either E- or Z-configured. Moreover, nucleophilic attack at the aldehyde group of the planar benzaldehyde can take place both from the Re or Si sides. Four products are therefore obtained. From the Z enolate the /-configured enantiomers A and B are the preferred products, whilst the E enolate gives predominately the w-configured enantiomers C and D. 

Studies have been made on the individual steps in this synthesis. Acetonation104 of L-sorbose was studied with respect to time, temperature and the presence of metal catalysts, among which aluminum and zinc were found beneficial. Solvent extraction105 was discovered as a means of separating the monoacetone derivative from the desired diacetone-L-sorbose (see page 117). Reichstein and Griissner103 condensed L-sorbose with formaldehyde, with 2-butanone and with benzaldehyde but they found the diacetone derivative to be the most satisfactory intermediate in their ascorbic acid synthesis. A crystalline dicyclohexylidene derivative has also been proposed in this connection.100... 

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.

One limitation encountered in synthetic studies of this reaction is the lack of chemoselectivity in the addition of aldehydes to unsymmetrically substituted furans. For example, the photochemical addition of benzaldehyde to 2-methylfuran provides a 1 3 1 mixture of oxetanes resulting from the exo addition of aldehyde to the more and less substituted alkenes, respectively. Ketone photocycloadditions are more selective. For instance, irradiation of 2-butanone and furan forms a 7 1 mixture of regioisomeric oxetanes (167) and (168) (1 1 mixture of epimers). 

Write the strucmral formulas for the following (a) 2-methylbutanal (b) propanal (c) o-methoxy-benzaldehyde (d) butanone (e) bromopropanone (f) 3-heptanone. 

Butanone 29 was also investigated as an aldol donor. The reactions of 2-buta-none 29 with nitro-substituted benzaldehydes afforded the aldol product 30 with excellent stereoselectivity (up to 93 7 of dr and 98% ee). However, the reaction also occurred unselectively at the Cl position of the ketone, leading to the concomitant formation of 31 (Scheme 8.10). 

Condensation catalyst. Muxfeldt el a I. 2 found this reagent a suitable basic catalyst for the condensation of benzaldehyde (1) with 2,2-dimethoxy-3-butanone (2) to produce the intermediates (3) and (4) and finally 4-phenylcyclopentane-l,2-dione (5). 

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