Acid From ketone

Polysubstituted 3-thiofiirans which are receiving a great interest as flavour and odour chemicals have been obtained by mono-//J5osubstitution and ortho-metallation from 3,4-dibromofuran <96T4065>. Dihydrofuran is used in a new synthesis of ketones from acids via acyl hemiacetals (Scheme 8, <96JOC6071>). 

Organometallic compounds or carbanions undergo a number of reactions in which the carbanion or carbanion-like moiety of the organometallic compound acts as a nucleophilic displacing agent. Examples are the formation of hydrocarbons from alkyl halides, alkyl halides from halogens, and ketones from acid chlorides or esters. The latter two reactions are closely related to the base-catalyzed condensations and are perhaps additions as well as displacement reactions. Related addition reactions are the carbonation of organometallic compounds and the addition to ketones or aldehydes. 

Organomanganese reagents can be used for the formation of ketones from acid chlorides with excellent functional group tolerance, the corresponding ketones isolated in good yield. Gallo et al. have reported some hetero-... 

The Cd powders can be used in the standard synthesis of ketones from acid chlorides. The advantage is that many functional groups are tolerated.1... 

D. A. Shirley, The Synthesis of Ketones from Acid Halides and Organometallic Compounds of Magnesium, Zinc and Cadmium, Organic Reactions 8, 28 (1954). 

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. 

D. A. Shirley, The synthesis of ketones from acid halides and organometallic compounds of magnesium, zinc, and cadmium, Org. React. 1954, 8, 28-58. 

Synthesis of Aldehydes and Ketones from Acid Chlorides... 

You met organocopper reagents in Chapter 10 where you saw that they did conjugate additions to a,p-unsaturated carbonyl compounds. Other metals, such as cadmium or manganese, can also be used to make ketones from acid chlorides. 

Distinguishing aldehydes and ketones from acid derivatives... 

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). 

The regioselective Baeyer-Villiger oxidation of acyclic aliphatic ketones normally results in the insertion of oxygen next to the bulkier alkyl chain. Since methyl is a poor migrating group, a common use of this reaction is to reduce the chain length of methyl ketones 1 two carbons to provide alcohols, after hydrolysis. The ability to synthesize methyl ketones from acids and med l-sutetituted alkenes (equation... 

Ketone synthesis. It has been an article of faith that Grignard reagents are too reactive to be useful for synthesis of ketones from acid chlorides. Actually the reaction affords ketones in almost quantitative yields when conducted in THF at -30 lo 78°.-... 

Methyl ketonesfrom carboxylic acid chlorides (3,112). Posner e/n/. report that the synthesis of ketones from acid chlorides and organocopper reagents is applicable to acid chlorides containing iodo, cyano, acyl, and carboalkoxy groups. The reaction, however,... 

Synthesis of ketones from acids, acid chlorides, cartxjnates vfa N-methoxyamides. 

Ketones from Acids.— Another important reaction of acids is the formation of ketones and aldehydes by the decomposition of salts of the acids. When calcium acetate is heated the calcium remains combined with part of the two carboxyl groups as calcium carbonate and the two alkyl radicals become united by the remaining carbonyl group forming a ketone. 

The synthesis of ketones from acid halides and organometallic compounds of magnesium, zinc and cadmium... 

O. R. 1-9, C. R. Hauser and B. E. Hudson, Jr., The Acctoacetic Ester Condensation and Related Reactions lV-4, S. M. McElvain, The Acyloins 11-4, W. S. Johnson, The Formation of Cyclic Ketones by Intramolecular Acylation VIII-2, D. A. Shirley, The Synthesis of Ketones from Acid Chlorides and Organometallic Compounds of Magnesium, Zinc, and Cadmium. ... 

The synthesis of ketones from acid chlorides has been demonstrated with several organometallic reagents (see Sections 1.13.3,1.13.4 and 1.13.5) however, the acylation of organolithiums often leads to substantid amounts of overaddition product. Initially, acid chlorides appear to be a poor choice for... 

A general method for the preparation of a-cyano ketones from acid halides was developed recently (equation 43).i57.i58 trimethylsilyl cyanide as reagent a great number of acyl cyanides can be prepared under mild conditions in high yield. In particular the synthetically useful aliphatic derivatives have become accessible by this reaction. Table 13 lists examples for aliphatic, a, -unsaturated and benzylic acyl cyanides. The procedure is very simple in that trimethylsilyl cyanide and acid chloride are mixed and kept without solvent. The reaction is followed by IR spectroscopy. As soon as all of the trimethylsilyl cyanide is consumed, the product can be isolated, normally by distillation, or directly used for fruther reactions. 

Methyl ketones from acids. A carboxylic acid or its lithium salt reacts with an alkyllithium to form a ketone. See next paragraph for an example. 

Use TEL production, synthesis of ketones from acid chlorides. 

---