Ketones, preparation from acid chlorides

This Asian species is a major agricultural pest. The pheromone has been proposed to consist of three male-specific compounds, only one of which, (Z)-exo-a-bergamotenal 150, has been reported in the literature [114]. The racemic compound was synthesized starting from farnesoic acid chloride 146 (Scheme 25) [114]. Thus, the vinyl ketene prepared from acid chloride 146 underwent 2+2 cycloaddition to give bicyclic ketone 147. The ketone function was removed by reaction with hydrazine followed by treatment of the resulting hy-... 

Acyl cyanides have been prepared from acid chlorides,a-halogenoketones, and a,jS-unsaturated acyl cyanides. Syntheses of a-cyanoketones from ketones, a,jS-unsaturated ketones, pyrroles, and 3-acylthioisoxazoles have been reported. 

Ketones can also be prepared from acid chlorides by reaction at low temperature with an excess of acid chloride. Tetrahydrofuran is the preferred solvent." The reaction conditions must be controlled to prevent formation of tertiary alcohol by addition of Grignard reagent to the ketone as it is formed. 

Pyridinethiolate esters, which are easily prepared from acid chlorides, also react with Grignard reagents to give ketones." ... 

The majority of catalytic enantioselective allylation reactions involve the chiral Lewis-acid-catalysed additions of allylsilanes or allylstannanes to carbonyl compounds. Monothiobinaphthol has been used by Woodward et al. as a chiral promoter in the enantioselective catalytic allylation of aryl ketones with impure Sn(allyl)4, prepared from allyl chloride, air-oxidised magnesium and SnCl4. Therefore, the allylation of arylketones in these conditions was achieved very efficiently, since the corresponding allylic alcohols were formed in... 

Mixed homocuprates.7 Mixed cuprates (1) in which the nontransferable ligand is an a-sulfonyl carbanion are easily prepared from dimethyl sulfone or methyl phenyl sulfone (equation I), and are effective for conjugate addition to enones and for a synthesis of ketones from acid chlorides. 

The metal lias to a great extent replaced zinc, which was used in 1849 by Frankland in the preparation of paraffin hydrocarbons and the zinc alkyls, and subsequently by Wagner for preparing secondary alcohol from aldehydes, by Saytzeff in preparing tertiary alcohols from ketones, and by Butlerow iu the preparation of both ketones and tertiary alcohols from acid chlorides. 

A list of ketones which have been prepared by the Friedel-Crafts stannic chloride method may be found in Table VI. Yields marked by an asterisk were obtained from acid chlorides prepared by the phosphorus pentachloride procedure all others were obtained from acid chlorides prepared from thionyl chloride. 

Alkynylsilanes can be converted into alkynylcoppers by treatment with Cu salts in an aprotic polar solvent such as l,3-dimethyl-2-imidazolidinone (DMI).62 The Cu-promoted coupling reactions via the Si-Cu transmetallation of alkynylsilanes are valuable for the syntheses of alkynyl ketones, 1,3-diynes, 1,3-enynes, and 1-aryl-l-alkynes from acid chlorides,62 alkynyl chlorides,63 alkenyl iodides,64 and aryl iodides,64 respectively (Equation (12)). In addition, symmetric 1,3-diynes can be prepared by the CuCl-mediated homocoupling of alkynylsilanes.65 653... 

The reagent forms the expected adducts with aldehydes and ketones in high yield. It can be used for preparation of t-butoxymethyl ketones from acid chlorides (equation 1). In combination with CuBr, it undergoes conjugate addition to a,p-enones (equation II). 

Symmetrical ketones are sometimes prepared from acyl chlorides by way of diketenes and /3-keto acids/ ... 

Grignard reagents themselves react readily with acid chlorides, but the products are usually tertiary alcohols these presumably result from reaction of initially formed ketones with more Grignard reagent. (If tertiary alcohols are desired, they are better prepared from esters than from acid chlorides. Sec. 20.21.) Organocadmium compounds, being less reactive, do pot react with ketones. 

The mercury and cadmium compounds are much less reactive than the lithium or magnesium systems, and are therefore useful for certain reactions where selectivity is important. The most widely applied example of this strategy is the preparation of ketones from acid chlorides and cadmium reagents. The cadmium reagent is useful because it is too unreactive to add to the product ketone, and the reaction therefore stops at the ketone stage. Scheme 5.5 lists some examples of this reaction. At... 

Victor Merz (Odessa, 12 December 1839-Ziirich, 25 May 1904) was associate professor (1869) and professor (1871) in the university of Zurich. He worked first on inorganic chemistry. He synthesised ketones from acid chlorides and hydrocarbons, sodium formate from carbon monoxide, and oxalic acid by heating alkali formates. He prepared aromatic carboxylic acids by distilling sulphonates with potassium cyanide and hydrolysing the nitriles produced, discovered a- and j8-naphthoic acids, and prepared j8-naphthyl-amine from j8-naphthol by the action of ammonia and zinc chloride. ... 

Dihydroxyalkanoic acids can be prepared by Lewis acid-catalysed condensations between aldehydes and tris(trimethylsiloxy)ethylene (Scheme 6). This approach, previously used to synthesize a-hydroxymethyl-ketones from acid chlorides, gives yields of 58—82% (five examples) and is non-stereoselective. 

In addition, ketones can be prepared from certain carboxylic acid derivatives, just as aldehydes can. Among the most useful reactions of this type is that between an acid chloride and a lithium diorganocopper reagent, R2CuLi. We ll discuss lithium diorganocopper reagents later in this chapter (Section 14.11) and will look at preparing ketones from acid chlorides in Section 16.4. 

The HCl generated in this reaction destroys one equivalent of diazomethane. This can be avoided by including a base, such as triethylamine, to neutralize the acid. Cyclic a-diazoketones, which are not available from acid chlorides, can be prepared by reaction of an enolate equivalent with a sulfonyl azide. Several types of compounds can act as the carbon nucleophile. These include the anion of the hydroxy-methylene derivative of the ketone or the dialkylaminomethylene derivative of the ketone. ... 

This method allows the preparation of ketones from acid chlorides containing other functional groups such as CO, CO2R, and CN, though some of these react slowly with organocadmium compounds under the conditions normally used. 

The acylpalladium complex formed from acyl halides undergoes intramolecular alkene insertion. 2,5-Hexadienoyl chloride (894) is converted into phenol in its attempted Rosenmund reduction[759]. The reaction is explained by the oxidative addition, intramolecular alkene insertion to generate 895, and / -elimination. Chloroformate will be a useful compound for the preparation of a, /3-unsaturated esters if its oxidative addition and alkene insertion are possible. An intramolecular version is known, namely homoallylic chloroformates are converted into a-methylene-7-butyrolactones in moderate yields[760]. As another example, the homoallylic chloroformamide 896 is converted into the q-methylene- -butyrolactams 897 and 898[761]. An intermolecular version of alkene insertion into acyl chlorides is known only with bridgehead acid chlorides. Adamantanecarbonyl chloride (899) reacts with acrylonitrile to give the unsaturated ketone 900[762],... 

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