Ketones aromatic methyl

The reaction of methyl ketones with a calculated amount of BTMA Br3 in aq. sodium hydroxide at room temperature and subsequent acid hydrolysis gave carboxylic acids together with bromoform in good yields. Aliphatic and aromatic methyl ketones have usually been reacted (Fig. 30) (ref. 38). 

Compound (B), being an oxidation product of a ketone should be a carboxylic acid. The molecular formula of (B) Indicates that it should be benzoic acid and compound (A) should, therefore, be a monosubstituted aromatic methyl ketone. The molecular formula of (A) indicates that it should be phenyl methyl ketone (acetophenone). Reactions are as follows ... 

Ketene dithioacetal 82 reacts with aromatic methyl ketones to generate thiopyranones. Further reaction with ethyl mercaptoacetate leads to the formation of thieno[3,2-f]pyranones in good yields (Scheme 18) <1997BML3101>. 

In a similar fashion, reductive alkylation of benzene, toluene, and xylenes with ben-zaldehyde, aromatic methyl ketones, and cycloalkanones can be induced by InCl3 in the presence of Me2SiClH 429... 

Phenyl formates (see Figure 11.34 for synthesis) hydrolyze to phenols more easily than the phenyl acetates shown in Figure 11.32. Overall, these species bring short reaction sequences to an end which may start with any aromatic methyl ketone or with an electron-rich aromatic aldehyde and which end with a phenol with widely variable substituent patterns. 

A convenient method for preparing alicyclic or aromatic methyl ketones consists in the acylation of the ethoxymagnesium derivative of diethyl malonate with the appropriate acyl chloride, followed by acid hydrolysis and decarboxylation of the resulting /3-keto diester. The last step is Carried out like the ketonic cleavage of /3-keto esters. The over-all yields are 60-85%. 

Arylacetones ate converted mostly to mixtures of chloroolefins, giving very little of the dichlotides. Aromatic methyl ketones yield mixtures of an a-chloro ketone and the monochloroolefin. ... 

A novel synthetic route for the preparation of unsymmetrically substituted benzophenones was developed in the laboratory of C.-M. Andersson utilizing an iron-mediated aromatic substitution as one of the key steps. The power of this method was demonstrated by the formal synthesis of the benzophenone moiety of the protein kinase C inhibitor balanol. In the late stages of the synthesis, it became necessary to convert the aromatic methyl ketone functionality of the highly substituted benzophenone substrate to the corresponding carboxylic acid. Bromine was added to sodium hydroxide solution, and the resulting sodium hypobromite solution was slowly added to the substrate at low temperature. Upon acidification the desired carboxylic acid was obtained in fair yield. 

Pybox L8 (Fig. 4) was synthesized from pyridine-2,6-dicarboxylic acid and optically active amino alcohols via an amido chloride intermediate [ 16,23 ] or via BFj-catalyzed cychzation of intermediate amino alcohols [24]. The combination of Pybox-i-Pr (L8a) and [Rh(COD)Cl]2 (Rl) exhibited catalytic activity as an in-situ catalyst for the reduction of acetophenone (Kl) to give 76% ee (S) [16].However, the complex RhCl3(Pybox-z-Pr) R4a under assistance with AgBF4 accelerated the reduction in THF to give 94-95% ees [23]. Diphenylsilane (SI) was also the best silane in this system. Most aromatic methyl ketones were reduced in 90-99% ees, and reactions of levurinate KIO and 2-octanone Kl 1 resulted in 95% ee and in 63% ee, respectively. The Pybox-Rh catalyst R4a reduced selectively 2-phenylcyclohexanone K12 to give the S-alcohols for both trans- and cis-isomers PI and P2 in 96-99% ees [25]. The catalyst R4a can differentiate only the enan-... 

In this section, we discuss a useful version of mixed ketone-aldehyde condensation, the reaction of aromatic methyl ketones with nonenolizable (usually aromatic) aldehydes. The prototype reaction is the condensation of acetophenone with benzaldehyde, leading to l,3-diphenylprop-2-en-l-one, chalcone (equation 81). The scope of this reaction is exceedingly broad the Nielsen-Houlihan review enumerates hundreds of examples comprising almost every imaginable combination of substituted acetophenone and aromatic aldehyde. - ... 

Dinitrogen tetroxide can be used to convert both aliphatic and aromatic methyl ketones into diacylfuroxans. For acetone the route of Scheme 1 was proposed the nitrolic acid was identified by its infrared spectrum, and the nitrile oxide was trapped as its 1,3-dipolar cycloadduct with dimethyl acetylenedicarboxylate.17 3... 

Aromatic methyl ketones can be halogenated at the a-position with Oxone and sodium halide, however, corr5>eting halogenation of the aromatic ring is significant. Q, a-Dichloroketones can be synthesized from alkynes by reaction with Oxone in HCl/DMF (eq 83). Oxone consistently gave better results than MCPBA for this transformation. 

These versatile reactions, commonly referred to as Stille and Suzuki couplings, respectively, are performed with organostannanes or organoboranes as nucleophiles and are tolerant to most functional groups. Ketones are obtained if carbon monoxide is present in the Stille reaction. This gives the possibility to label an aromatic methyl ketone in two different positions by the use of either [ C] carbon monoxide or [ C] methyl iodide, as shown in O Fig. 41.22 (Andersson et al. 1995 Andersson and Langstrom 1995a, b). 

As already demonstrated by the several examples reported for the formation of five-membered rings, free-radical reactions are usefiol tools for the functionalization of C6o- It is possible to synthesize C6o-fused tetra-hydroazepinones 89 (conversion in parenthesis) via a radical process mediated by Cu(OAc)2 using N-sulfonylated o-amino-aromatic methyl ketones 88 (140L1020). Similar compounds can be obtained also through Pd(ll) catalyzed cyclization of N-sulfonyl-2-aminobiaryls with Cso (12ASC2473). 

Ketones are more challenging substrates than aldehydes in the allylation reactions because of the less reactivity of the former. The BlNOL-TiCl2 complex has been shown to catalyze the addition of tetraallyltin to aromatic methyl ketones with moderate enantioselectivities [90]. Walsh found that the presence of a large excess of 2-propanol (20 equiv relative to the ketone) has a favorable impact on the enantioselectivity of the reaction and the enantiomeric excess of the product could be improved up to 96% [91]. 2,2 -bis(tritylamino)-4,4 -dichlorobenzophenone... 

The haloform reaction is a good method for the oxidation of aliphatic methyl ketones or of methyl carbinols to carboxylic acids. The reaction is also applicable to aromatic methyl ketones and aryl methyl carbinols obtained by the Friedel-Crafts reaction and by the Grignard reaction, respectively. 

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