Methyl tert-butyl ketone

If, on the other hand, unsymmetrically substituted carbonyl compounds such as monosubstituted benzophenones (X = OCH3, CH3, Cl), tert-butyl methyl ketone, acetophenone, acetaldehyde, or benzaldehyde are used for trapping 39a, diastere-omeric mixtures are formed in each case they could all be resolved except for the products obtained with p-methoxybenzophenone and acetophenone 33>. An X-ray structure analysis has been performed for the E-isomer 57g 36) which, in conjunction with H-NMR studies, permitted structural assignment in cases 56 and 57e, g and h35>. Additional chemical evidence for the structure of the six-membered heterocycles is provided by the thermolysis of 56 a considered in another context (see Sect. 3.1). In general the reaction 39a- 56 or 57 is accompanied by formation of phosphene dimers, presumably via [4 + 4]- and via [4 + 2]-cycloaddition 35). 

Aliphatic Ketones The asymmetric hydrogenation of simple aliphatic ketones remains a challenging problem. This may be attributed to the difficulty with which the chiral catalyst differentiates between the two-alkyl substituents of the ketone. Promising results have been obtained in asymmetric hydrogenation of aliphatic ketones using the PennPhos-Rh complex in combinahon with 2,6-lutidine and potassium bromide (Tab. 1.11) [36]. For example, the asymmetric hydrogenation of tert-butyl methyl ketone affords the requisite secondary alcohol in 94% ee. Similarly, isopropyl, Butyl, and cyclohexyl methyl ketones have been reduced to the corresponding secondary alcohols with 85% ee, 75% ee, and 92% ee respectively. 

Table 2.5 Comparison between equilibrium (eq) and nonequilibrium (neq) B3LYP/6-3IC(d) intensity shifts (km mob ) with respect to the gas phase for dimethyl ketone (DMK), methyl ethyl ketone (MEK), sec-butyl methyl ketone (SBMK) and tert-butyl methyl ketone (TBMK). Experimental data from ref [53] are also shown for comparison...

The number of publications describing new ligands that allow the transfer hydrogenation of aromatic ketones with over 90 % ee has grown in leaps and bounds since 1996 [15]. In these reactions the use of ruthenium [15a-f] and iridium [15g] as the catalytically active metals has recently been augmented by the use of phosphorus-free ligands such as chiral diamines, amino alcohols, and bisthioureas such as 7 [15a,e-g]. A ruthenium-catalyzed transfer hydrogenation with 92 % ee has even been reported for the aliphatic ketone pinacolone (tert-butyl methyl ketone) [16]. 

Some progress has been made, particularly with the ruthenium complex-catalyzed transfer hydrogenation [56] For tert-butyl methyl ketone as the first purely aliphatic ketone the bench mark of 90 % ee has been crossed by application of the oxazolinylferrocenylphosphine 28 the transfer hydrogenation by isopropanol under reflux in the presence of sodium hydroxide resulted in 93 % ee (S)-3,3-dimethyl-butan-2-ol [57]. For alkyl aryl ketones 92-95 % ee is obtained with... 

Strong CIDNP effects may be observed during photolysis of dialkyl ketones and an example will be treated in this Section. Fig, 8a shows an NMR spectrum taken during irradiation of a 0.7 M solution of tert.-butyl methyl ketone (pinacolone) in benzene with the unfiltered light of a high pressure mercury lamp 3). When compared with the spectrum taken after 20 minutes ir-... 

Fig. 8. CIDNP during photolysis of tert.-butyl-methyl ketone 0.7 M in benzene...

D.18) 2-Butanone, 3,3-dimethyl-, 3,3-dimethylbutan-2-one, tert-butyl methyl ketone, 2,2-dimethylbutanone, trimethylacetone, pinacoline, pinacolone 75-97-8]... 

Beilstein Handbook Reference) AI3-03075 BRN 1209331 t-Butyl methyl ketone tert-Butyl methyl ketone EINECS 200-9204 HSDB 5210 Ketone, t-butyl methyl Ketone, tert-butyl methyl Methyl t-butyl ketone Methyl tert-butyl ketone NSC 935 Pinacolin Pinacoline Pinacolone Pinakolin. Used in chemical synthesis, manufacture. Liquid mp = -52.5° bp = 106.1° d = 0.7229 slightly soluble in H2O (2.5 g/100 ml), more soluble in organic solvents LD50 (rat orl) = 610 mg/kg. Lancaster Synthesis Co. Mallinckrodt inc. Sigma-Aldrich Fine Chem. 

If the ketone is blocked on one side so that it cannot enolize—in other words it has no protons on that side—only one aldol reaction is possible. Ketones of this type might bear a tertiary alkyl or an aryl substituent. tert-Butyl methyl ketone (3,3-dimethylbutan-2-one), for example, gives aldol reactions with various bases in 60-70% yield. Enolization cannot occur towards the f-butyl group and must occur towards the methyl group instead. 

Hexane. 3500—1300 cm. Thin film 2-Methylpentane. 3500—1300 cm . Thin film Dec-l-ene. 3500—1300 cm. Thin film /rfl 5-Stilbene. 1300—400 cm". KBr disc Styrene. 3500—1300 cm". Thin film Styrene 1300—400 cm". Thin film Phenyl Acetylene. 3500—1300 cm". Thin film Phenyl Acetylene. 1300—400 cm". Thin film Aromatic substitution patterns. 2000—1600 cm" para-Cresol. 3500—1300 cm". I.M. CCI4 solution tert-Butyl methyl ketone. 4000—650 cm". Thin film -Heptaldehyde. 4000—650 cm". Thin film Di-/sopropyl ether. 4000—650 cm". Thin film Acetic Anhydride. 4000—650 cm". Thin film Propionic acid. 4000—650 cm". Thin film Propionic acid. 3500—2000 cm". Solution 0.005M CCI4 Methyl salicylate. 4000—650 cm . Thin film n-Butylamine. 4000—650 cm". Thin film Benzamide. 3500—1300 cm". KBr disc Methionine. 4000—650 cm". KBr disc Benzonitrile. 3500—1300 cm". Thin film Benzonitrile. 1300—400 cm". Thin film A-Methyl acetamide. 3500—650 cm". Thin film Methyl acrylate. 4000—650 cm". Thin film Benzoyl chloride. 4000—650 cm". Thin film Triphenyl phosphate. 3500—1300 cm". Melt Triphenyl phosphate. 1300—400 cm". Melt Di-wopropyl sulphone. 4000—650 cm". Melt Nitrobenzene. 4000—650 cm". Thin film Dimethyl sulphoxide. 4000—650 cm". Thin film Polymeric silicone. 4000—650 cm". Thin film Calcium sulphate Dihydrate. 4000—650 cm". KBr disc... 

Note Abbreviations Dimethyl ketone (DMK), methyl ethyl ketone (MEK), ec-buthyl methyl ketone (SBMK), and tert-butyl methyl ketone (TBMK). Experimental data from ref. 215. 

Yamamoto has recently described a novel catalytic, asymmetric aldol addition reaction of enol stannanes 19 and 21 with aldehydes (Eqs. 8B2.6 and 8B2.7) [14]. The stannyl ketones are prepared solvent-free by treatment of the corresponding enol acetates with tributyltin methoxide. Although, in general, these enolates are known to exist as mixtures of C- and 0-bound tautomers, it is reported that the mixture may be utilized in the catalytic process. The complexes Yamamoto utilized in this unprecedented process are noteworthy in their novelty as catalysts for catalytic C-C bond-forming reactions. The active complex is generated upon treatment of Ag(OTf) with (U)-BINAP in THE Under optimal conditions, 10 mol % catalyst 20 effects the addition of enol stannanes with benzaldehyde, hydrocinnamaldehyde, or cinnamaldehyde to give the adducts of acetone, tert-butyl methyl ketone (pinacolone), and acetophenone in good yields and 41-95% ee (Table 8B2.3). 

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